NHA Phlebotomy Technician (CPT) — All Questions

A phlebotomist must collect a blood culture set, a PT/INR, a basic metabolic panel on a gel serum tube, and a CBC. Which collection sequence follows the standard order of draw?

• a.Blood culture, light blue, gel serum tube, lavender✓
• b.Light blue, blood culture, lavender, gel serum tube
• c.Gel serum tube, blood culture, light blue, lavender
• d.Lavender, light blue, blood culture, gel serum tube

The standard order of draw is blood culture (sterile) first, then the light blue sodium citrate coagulation tube, then serum tubes with or without gel, then heparin, then EDTA, then glycolytic inhibitor tubes. Drawing the blood culture first protects it from skin-flora contamination introduced by non-sterile tube handling. Every other sequence listed allows additive carryover into a tube where that additive causes error, most notably EDTA carried into a chemistry or coagulation tube.CLSI GP41

A phlebotomist accidentally draws the lavender EDTA tube before the light blue citrate tube. What is the most likely consequence for the coagulation results?

• a.The specimen will clot in the light blue tube within seconds
• b.There is no effect because both tubes contain anticoagulants
• c.The PT and aPTT will be falsely shortened by the added EDTA
• d.EDTA carryover chelates calcium and can falsely prolong the PT and aPTT✓

EDTA is a potent calcium chelator, and even a trace carried over on the needle into the citrate tube removes additional calcium and can falsely prolong clotting times. It may also falsely raise potassium and lower calcium if carried into a chemistry tube. The tubes are not interchangeable simply because both are anticoagulated; each anticoagulant works by a different mechanism and only citrate is validated for routine coagulation testing.CLSI GP41

A patient has small veins and the phlebotomist leaves the tourniquet in place while palpating for two full minutes. What analytic problem is most likely?

• a.Dilution of the specimen with interstitial fluid
• b.Loss of platelets from the sample
• c.Hemoconcentration with falsely elevated protein, calcium and potassium✓
• d.Complete clotting of the EDTA specimen

The tourniquet should stay on no longer than one minute; beyond that, plasma water leaves the vessel and protein-bound and cellular analytes concentrate. This produces falsely elevated total protein, albumin, calcium, potassium and hematocrit. Tourniquet time does not dilute the sample or cause the EDTA tube to clot, and platelets are not selectively lost.CLSI GP41

Which antecubital vein is the first choice for routine venipuncture in an adult?

• a.Median cubital vein✓
• b.Basilic vein
• c.Radial vein
• d.Brachial vein

The median cubital vein is selected first because it is usually large, well anchored, close to the surface and farthest from the brachial artery and median nerve. The basilic vein is the last antecubital choice precisely because the artery and nerve lie beneath it. The brachial and radial vessels are deep or arterial and are not used for routine venipuncture.CLSI GP41

At what angle to the skin should the needle be inserted for a routine antecubital venipuncture?

• a.90 degrees
• b.15 to 30 degrees✓
• c.5 degrees or less
• d.45 to 60 degrees

A 15 to 30 degree angle allows the bevel to enter the vein lumen without passing through the far wall. An angle that is too shallow causes the needle to ride on top of the vein and fail to enter; an angle of 45 degrees or more risks going through the vein and into underlying structures. A 90 degree insertion is used for dermal puncture devices, not for venipuncture.CLSI GP41

Which needle gauge range is standard for routine adult venipuncture with an evacuated tube system?

• a.25 to 27 gauge
• b.16 to 18 gauge
• c.18 to 20 gauge
• d.21 to 23 gauge✓

Gauges 21 to 23 are standard: 21 is the general-purpose size, 22 is used for smaller or fragile veins, and 23 is typical of a winged (butterfly) set. Larger bores such as 16 to 18 gauge are used for blood donation or infusion and are unnecessarily traumatic for diagnostic draws. Very small bores like 25 gauge force cells through a narrow lumen and cause hemolysis.CLSI GP41

A provider orders a lactate and a blood alcohol level. Which tube additive combination is designed to preserve these analytes?

• a.K2 EDTA
• b.Lithium heparin
• c.Sodium citrate
• d.Sodium fluoride and potassium oxalate✓

The gray-top tube contains sodium fluoride, an antiglycolytic agent that stops cells from consuming glucose or generating lactate, plus potassium oxalate as the anticoagulant. Citrate is for coagulation testing, heparin for stat chemistry, and EDTA for hematology; none of them inhibit glycolysis. Note that a non-alcohol antiseptic must also be used when collecting a blood alcohol.CLSI GP41

The light blue stopper tube used for PT/INR and aPTT contains which additive, and why must it be filled completely?

• a.Sodium citrate, because a fixed 9:1 blood-to-anticoagulant ratio is required✓
• b.Thrombin, because clotting must be accelerated
• c.EDTA, because underfilling shrinks the red cells
• d.Heparin, because it must be balanced against the plasma volume

Sodium citrate reversibly binds calcium and requires a 9 parts blood to 1 part anticoagulant ratio. An underfilled tube leaves excess citrate that binds reagent calcium during testing and falsely prolongs the PT and aPTT. Heparin and EDTA are not used for routine coagulation, and thrombin is found in rapid-serum tubes, not coagulation tubes.CLSI GP41

A comprehensive metabolic panel is ordered. Which tube is appropriate and what does it contain?

• a.Gray tube containing sodium fluoride
• b.Light blue tube containing sodium citrate
• c.Gold or tiger-top serum separator tube containing a clot activator and gel✓
• d.Lavender tube containing K2 EDTA

Chemistry panels are run on serum from a serum separator tube, which holds a clot activator plus a thixotropic gel that forms a barrier between serum and cells after centrifugation. Citrate tubes are for coagulation, EDTA for hematology, and fluoride for glucose and alcohol preservation. Using an anticoagulated tube in place of the SST changes several chemistry values.CLSI GP41

A stat ammonia level is ordered. Which tube is used and where does it fall in the order of draw?

• a.Green heparin tube, drawn after serum tubes and before EDTA✓
• b.Lavender EDTA tube, drawn before the serum tube
• c.Light blue citrate tube, drawn first
• d.Gray fluoride tube, drawn before heparin

Ammonia is collected in a heparin tube, and heparin tubes are drawn after serum tubes and before EDTA in the standard order. The specimen must also be placed on ice and delivered promptly because ammonia rises quickly at room temperature. EDTA, citrate and fluoride tubes are not appropriate for ammonia and none of them occupy the heparin position in the sequence.CLSI GP41

Which group of tests is collected in the lavender EDTA tube?

• a.Comprehensive metabolic panel and lipid panel
• b.Glucose, lactate and blood alcohol
• c.CBC, hemoglobin A1c and ESR✓
• d.PT, aPTT and fibrinogen

EDTA preserves cell morphology and prevents platelet clumping, so it is the tube of choice for the CBC, hemoglobin A1c and the erythrocyte sedimentation rate. Coagulation tests require citrate, glucose and alcohol require a fluoride tube, and chemistry panels require serum or heparinized plasma. Substituting EDTA for a chemistry tube falsely raises potassium and falsely lowers calcium.CLSI GP41

What is the maximum lancet penetration depth for a heel stick on a newborn?

• a.2.0 mm✓
• b.5.0 mm
• c.3.5 mm
• d.There is no depth limit if the heel is warmed

Penetration must not exceed 2.0 mm because the calcaneus in a newborn may lie only 2 to 3 mm below the plantar skin, and bone contact can cause osteomyelitis. Depths of 3.5 mm or 5 mm greatly increase that risk. Warming the heel improves blood flow but does not change the safe depth limit.CLSI GP42

A phlebotomist is preparing a heel stick on a two-day-old infant. Which site is acceptable?

• a.The posterior curvature of the heel
• b.The medial or lateral plantar surface of the heel✓
• c.The great toe
• d.The arch of the foot

Only the medial and lateral plantar surfaces of the heel are used, because the calcaneus does not extend into these areas. The posterior curvature sits directly over the bone, and the arch overlies nerves, tendons and cartilage. The great toe and other fingers or toes are not acceptable dermal puncture sites in a newborn.CLSI GP42

During a capillary collection the phlebotomist must fill a lavender microtube and a serum microtube. Which order is correct?

• a.Both must be filled at the same time from separate punctures
• b.Either order, because capillary blood has no additive carryover
• c.Lavender microtube first, then serum✓
• d.Serum microtube first, then lavender

The capillary order of draw differs from venipuncture: after any blood gas specimen, EDTA is collected first so that platelets are captured before they aggregate at the puncture site, followed by other additive tubes and finally serum. Filling the serum tube first would leave a clumped, unrepresentative platelet count. Carryover and clotting both occur in capillary work, so order does matter and a second puncture is not required.CLSI GP42

A phlebotomist cleans the site with 70% isopropyl alcohol and inserts the needle immediately while the skin is still wet. What is the most likely result?

• a.The venipuncture will be less painful for the patient
• b.Stinging for the patient and hemolysis of the specimen✓
• c.The antiseptic effect will be improved
• d.The specimen will clot faster in the tube

Alcohol must air dry for about 30 seconds so it can kill organisms and so residual alcohol is not carried into the vein. Wet alcohol stings on needle entry and lyses red cells, producing hemolysis that falsely raises potassium, LDH and AST. Drying is part of the antiseptic action, so puncturing early reduces rather than improves disinfection.CLSI GP41

Which skin antisepsis is appropriate before collecting blood cultures from an adult?

• a.Soap and water only
• b.A single wipe of 70% isopropyl alcohol
• c.No antisepsis is needed because the bottles are sterile
• d.Chlorhexidine gluconate applied with friction and allowed to dry completely✓

Blood cultures require an antiseptic effective against resident skin flora, and chlorhexidine gluconate applied with friction and fully dried is the standard for patients older than two months. A quick alcohol wipe alone does not reduce skin flora enough and leads to false-positive contaminated cultures. Sterile bottles do not protect against organisms carried in on the needle from unprepared skin.CLSI GP41

An inpatient has an IV infusing in the left forearm and no accessible veins in the right arm. What is the best action?

• a.Cancel the order and document that no site was available
• b.Ask the nurse to stop the infusion, wait at least two minutes, then draw below the IV and discard the first 5 mL✓
• c.Draw from the IV line without flushing it
• d.Draw directly above the IV site with the infusion running

When no other site exists, the infusion is stopped by licensed personnel, a short wait allows the fluid to clear, the draw is made distal to the IV so blood has not passed the infusion point, and a discard volume clears residual fluid. Drawing above a running IV dilutes the specimen with infusate. Drawing from a line without flushing gives contaminated results, and simply canceling the order abandons a resolvable problem.CLSI GP41

A patient had a right mastectomy with lymph node removal 14 months ago and has an IV in the left hand. What should the phlebotomist do?

• a.Consult the patient's provider for guidance before selecting a site✓
• b.Draw above the IV in the left arm
• c.Draw from the right antecubital area since the surgery was over a year ago
• d.Use a fingerstick on the right hand without asking anyone

Lymph node dissection impairs lymph drainage indefinitely, so the affected side is avoided because of infection and lymphedema risk, and there is no automatic time limit that makes it safe. With the only other arm carrying an IV, the correct step is to obtain provider direction rather than choose unilaterally. Drawing above an IV dilutes the sample, and a fingerstick on the affected side carries the same restriction as a venipuncture.CLSI GP41

Why is the basilic vein the last antecubital choice for venipuncture?

• a.It is too small to accommodate a 21 gauge needle
• b.The brachial artery and median nerve lie close beneath it✓
• c.It collapses under vacuum more easily than other veins
• d.It contains more valves than any other arm vein

The basilic vein sits on the medial side of the antecubital fossa directly over the brachial artery and near the median nerve, so puncture there carries the highest risk of arterial nicking and nerve injury. Size, collapse tendency and valve count are not the deciding factors. When the basilic vein must be used, the needle is anchored carefully and the patient is monitored for shooting pain.CLSI GP41

A light blue tube is filled only two thirds of the way because the vein collapsed. What should the phlebotomist do?

• a.Add saline to the tube to reach the fill line
• b.Send it and note 'short draw' on the requisition
• c.Discard the tube and recollect a properly filled citrate tube✓
• d.Pour the contents into a second light blue tube to reach the fill line

A short-filled citrate tube violates the required 9:1 ratio and produces falsely prolonged PT and aPTT results, so it must be recollected rather than reported with a comment. Combining two partially filled tubes doubles the anticoagulant relative to blood and makes the error worse. Adding any diluent to an evacuated tube is never acceptable because it alters both the ratio and the analyte concentration.CLSI GP41

How should an EDTA tube be mixed immediately after collection?

• a.Invert once and place upright in the rack
• b.Invert gently 8 to 10 times✓
• c.Do not mix; the additive dissolves on its own
• d.Shake vigorously five times

EDTA tubes require roughly 8 to 10 gentle inversions so the anticoagulant coats all the blood and microclots do not form. Vigorous shaking introduces mechanical trauma and hemolysis, which invalidates many tests. A single inversion or no mixing at all leaves clotted or clumped specimens that the laboratory must reject.CLSI GP41

A phlebotomist collects an aerobic and anaerobic blood culture set, then a green heparin tube, then a light blue citrate tube. What is the main problem?

• a.Heparin and citrate tubes cannot be drawn during the same venipuncture
• b.The citrate tube was drawn after heparin, so heparin carryover can prolong clotting times✓
• c.Blood cultures should never be drawn first
• d.There is no problem; the sequence is correct

The citrate tube must immediately follow the blood cultures and precede all serum and heparin tubes. Because heparin inhibits thrombin, carryover into the citrate tube can falsely prolong the aPTT. Blood cultures are correctly drawn first, and both tubes may be collected in one venipuncture as long as the sequence is respected.CLSI GP41

A phlebotomist has just filled a light blue citrate tube. According to the standard order of draw, which tube is collected next?

• a.Gold serum separator tube✓
• b.Gray sodium fluoride tube
• c.Green heparin tube
• d.Lavender EDTA tube

After the citrate tube, serum tubes with or without a gel separator are collected, followed by heparin, then EDTA, then the fluoride tube. Placing EDTA or fluoride earlier risks carrying potassium-containing or oxalate additives into chemistry tubes. Heparin also follows, not precedes, the serum tube in the standard sequence.CLSI GP41

A patient is told to pump the fist repeatedly while the tourniquet is on. Which result is most affected?

• a.Sodium, which may be falsely decreased
• b.Hemoglobin, which may be falsely decreased
• c.Platelet count, which may be falsely elevated
• d.Potassium, which may be falsely elevated✓

Vigorous fist pumping causes muscle cells to release potassium into the local circulation, so the measured potassium can be falsely high. Patients may make a fist once to help the vein, but repeated pumping is discouraged. Hemoglobin, sodium and platelet counts are not meaningfully changed by this mechanism.CLSI GP41

A coagulation specimen is the only tube ordered and a winged blood collection set will be used. What should be done first?

• a.Fill the citrate tube directly, since the tubing volume is negligible
• b.Use a 25 gauge needle to slow the fill rate
• c.Remove the tourniquet before attaching the citrate tube
• d.Draw and discard a tube first to prime the tubing air space✓

The air in a winged set's tubing displaces blood from the first tube, so a discard tube is drawn first to prime the line and preserve the 9:1 fill ratio. Filling the citrate tube directly would underfill it and falsely prolong clotting times. The tourniquet stays on until blood flow is established, and a 25 gauge needle is too small and would cause hemolysis.CLSI GP41

The last tube is filling. In what order should the phlebotomist complete the venipuncture?

• a.Remove the last tube, release the tourniquet, then withdraw the needle and apply pressure✓
• b.Release the tourniquet, remove the needle, then remove the last tube
• c.Apply pressure to the site, then remove the needle and tourniquet together
• d.Remove the needle, release the tourniquet, then remove the last tube

The tube is removed from the holder first so no vacuum pulls on the vein, the tourniquet is released next to lower venous pressure, and only then is the needle withdrawn and pressure applied. Pulling the needle out with the tourniquet still tight forces blood into the tissue and causes a hematoma. Removing a tube after the needle is out is impossible, and pressure cannot be applied while the needle is still in the vein.CLSI GP41

A 4-year-old needs a CBC and a basic metabolic panel. Which approach best matches pediatric practice?

• a.Use an 18 gauge needle to finish quickly
• b.Draw from a foot vein without provider approval
• c.Use a 23 gauge winged set with small-volume tubes and secure, gentle immobilization✓
• d.Apply the tourniquet for three minutes to enlarge the vein

Children have small, mobile veins and a limited total blood volume, so a 23 gauge winged set with pediatric-volume tubes reduces trauma and blood loss. A large 18 gauge needle is unnecessarily traumatic, prolonged tourniquet time causes hemoconcentration, and lower-extremity draws require provider authorization. Comforting and safely holding the child also improves success on the first attempt.CLSI GP41

An 88-year-old patient has thin skin, fragile veins and takes warfarin. Which modification is most appropriate?

• a.Slap the arm firmly to raise the vein
• b.Apply the tourniquet as tightly as possible
• c.Use a 16 gauge needle so the draw finishes faster
• d.Anchor the vein without dragging the skin, use a 23 gauge winged set, and hold pressure longer after the draw✓

Older skin tears easily and anticoagulated patients bleed longer, so gentle anchoring, a smaller winged needle and extended pressure after needle removal are appropriate. Slapping the arm and overtightening the tourniquet bruise fragile tissue and can rupture the vein. A large bore needle increases trauma without any benefit for a routine draw.CLSI GP41

A requisition lists the patient name and tests but has no ordering provider and no collection priority. What should the phlebotomist do?

• a.Collect the specimens and write in a provider name from the chart
• b.Collect the specimens and let the laboratory sort it out
• c.Stop and have the incomplete requisition corrected before collecting✓
• d.Collect only the tests the phlebotomist recognizes

Laboratory testing must be performed on an authorized, complete order, so an incomplete requisition is clarified with the ordering source before any blood is drawn. Writing in information the phlebotomist did not receive from the provider falsifies the record. Collecting first and deferring the problem risks an unauthorized draw and a redraw for the patient.CLIA

How should the needle be positioned as it enters the skin during venipuncture?

• a.Bevel down and against the direction of blood flow
• b.Bevel up and in line with the vein, pointing toward the heart✓
• c.Bevel up but angled across the vein at 45 degrees
• d.Bevel sideways at 90 degrees to the vein

The bevel faces up and follows the long axis of the vein so the sharpest point enters first and the opening sits inside the lumen. Bevel-down entry can occlude the opening against the vein wall and stop flow. Crossing the vein at a steep or perpendicular angle increases the chance of going through the far wall and causing a hematoma.CLSI GP41

A phlebotomist has attempted venipuncture twice on the same patient without obtaining blood. What is the correct next step?

• a.Attempt a third and fourth time on the same arm
• b.Stop and ask another qualified phlebotomist to attempt the draw✓
• c.Probe laterally with the needle already in place until blood appears
• d.Send the patient home and cancel the tests

Standard practice limits a phlebotomist to two attempts before handing the patient to another qualified collector, which protects the patient from repeated trauma. Blind lateral probing risks nerve damage and arterial puncture and is never acceptable. Canceling ordered tests without escalation deprives the provider of needed results.CLSI GP41

Blood flow stops shortly after a good flash is seen. Which corrective action is appropriate?

• a.Move the needle rapidly side to side to find the vein
• b.Ask the patient to pump the fist continuously for one minute
• c.Pull the needle nearly out and reinsert it at a new angle
• d.Rotate the needle slightly or advance it a small amount, and confirm the tube is fully seated✓

Loss of flow is often caused by the bevel resting against a vein wall, a partially seated tube or a collapsed vein, so gentle rotation, slight advancement or reseating the tube usually restores flow. Withdrawing and reinserting or moving the needle laterally can lacerate the vein and injure nerves. Continuous fist pumping falsely elevates potassium and does not solve a positional problem.CLSI GP41

Which fingerstick technique is correct for an adult capillary glucose?

• a.Puncture the center of the fingertip parallel to the fingerprint lines
• b.Puncture the tip of the fifth finger
• c.Puncture the side of the fleshy pad of the third or fourth finger, across the fingerprint lines✓
• d.Puncture the thumb because it has the best blood supply

The side of the fleshy pad of the middle or ring finger is used, and the puncture crosses the fingerprint lines so the drop forms rather than running along a groove. The very center of the fingertip is the most nerve-dense and painful area. The fifth finger has little tissue over bone and the thumb has a pulse and thicker calluses, so both are avoided.CLSI GP42

A legal blood alcohol specimen is ordered. Which site preparation is required?

• a.A non-alcohol antiseptic such as povidone-iodine or soap and water✓
• b.No cleaning at all, to avoid contaminating the sample
• c.70% isopropyl alcohol allowed to dry for one minute
• d.Alcohol followed by chlorhexidine

Alcohol-based antiseptics can contaminate the specimen and cast doubt on a legally defensible result, so a non-alcohol antiseptic is used. Chlorhexidine preparations frequently contain alcohol, so combining them does not solve the problem. Skipping antisepsis entirely violates infection control and would itself invalidate the collection.CLSI GP41

An order requires a lavender EDTA tube and a gray fluoride tube only. Which sequence is correct and why?

• a.Gray first, because it is the smallest tube
• b.Gray first, because the fluoride preserves glucose better when drawn early
• c.Either order, because neither additive affects the other
• d.Lavender first, because EDTA precedes the glycolytic inhibitor tube in the order of draw✓

In the standard sequence the EDTA tube always precedes the sodium fluoride and potassium oxalate tube, which is drawn last. Potassium oxalate carried backward into an EDTA tube can distort cell morphology and hematology results. Tube size and how early the fluoride is drawn have no bearing on the required order.CLSI GP41

A lavender EDTA tube is drawn before the gold gel serum tube and a small amount of EDTA is carried over. Which pattern of chemistry results is most consistent with that carryover?

• a.Potassium and calcium both falsely elevated, because EDTA salts preserve cations in the sample
• b.Potassium falsely elevated and calcium falsely decreased by the chelating additive✓
• c.Sodium falsely elevated and chloride falsely decreased by the added salt load
• d.Glucose falsely decreased because EDTA allows the red cells to keep consuming it

The common EDTA salts are dipotassium and tripotassium EDTA, so carryover adds potassium directly to the specimen and the reported potassium runs high. EDTA works by chelating calcium, so the calcium available for measurement is bound and the reported calcium runs low. Magnesium and alkaline phosphatase are affected the same way. Nothing in EDTA adds sodium or chloride, and EDTA does not inhibit glycolysis, so a glucose shift is not the signature of this error.CLSI GP41

A light blue sodium citrate tube for a PT/INR is filled to only about two thirds of its stated draw volume and is sent to the laboratory anyway. What effect does the short fill have on the result?

• a.The prothrombin time is falsely shortened because less anticoagulant reaches the plasma sample
• b.The prothrombin time is unaffected as long as the tube was inverted the correct number of times
• c.The prothrombin time is falsely prolonged, so the reported INR is too high✓
• d.The specimen clots in the tube, so no prothrombin time can be reported at all

The tube is manufactured so that a full draw gives nine parts blood to one part citrate. A short draw leaves the same fixed volume of citrate in a smaller volume of plasma, so excess citrate is still binding calcium when the laboratory adds its calcium-containing reagent. Clotting is therefore delayed and the time is reported longer than the patient's true value, which can lead a prescriber to reduce a warfarin dose that did not need reducing. Mixing does not correct a ratio problem, and a short draw does not by itself clot the specimen.CLSI GP41

By what mechanism does the heparin in a green stopper tube keep the specimen from clotting?

• a.It chelates the calcium in the specimen so that the coagulation cascade cannot proceed
• b.It coats the tube wall so platelets cannot adhere and form a clot
• c.It precipitates fibrinogen out of the plasma before the fibrin mesh can form
• d.It accelerates antithrombin, which then inhibits thrombin and factor Xa✓

Heparin is the only common tube anticoagulant that works by potentiating a natural inhibitor rather than by removing calcium. It binds antithrombin and greatly speeds that inhibitor's neutralisation of thrombin and factor Xa, so fibrin never forms. Chelation of calcium is how EDTA, citrate and oxalate work. Heparin does not precipitate fibrinogen, and no tube additive prevents clotting merely by coating the glass.

A gray stopper tube contains sodium fluoride and potassium oxalate. What does each of those two chemicals do?

• a.Fluoride inhibits glycolysis and preserves glucose; oxalate is the anticoagulant✓
• b.Fluoride is the anticoagulant; oxalate stabilises the red cell membrane
• c.Both act as anticoagulants, and the pair is used only because it is cheaper to produce
• d.Fluoride sterilises the specimen; oxalate keeps the glucose from crossing into the cells

Sodium fluoride is a preservative, not an anticoagulant: it blocks the glycolytic pathway so the red and white cells stop consuming glucose, which is why this tube is used for glucose, lactate and blood alcohol. Potassium oxalate does the anticoagulating, by precipitating calcium. Naming either chemical for the other job is the usual error, and fluoride has no meaningful sterilising or membrane-stabilising role at the concentration used.

Blood culture bottles and the yellow stopper sterile tube contain SPS. Besides preventing clotting, what does SPS contribute to a culture?

• a.It supplies the nutrients and the growth factors that an organism needs in order to multiply
• b.It lyses the red cells so that any organisms trapped inside them are released
• c.It inhibits complement, phagocytes and some antibiotics, so organisms survive to grow✓
• d.It selectively kills normal skin flora and leaves true pathogens undisturbed

Sodium polyanethol sulfonate anticoagulates and, just as importantly, blunts the blood's own antibacterial defences and some aminoglycoside activity, so a small number of organisms can still multiply in the bottle. It is not a nutrient; the broth in the bottle provides that. It does not lyse red cells, and no additive can tell a contaminating skin organism from a true pathogen, which is why careful skin antisepsis and two separate sites still matter.CLSI M47

A provider orders a serum lithium level on a patient taking lithium carbonate. Which tube choice matters here, and why?

• a.Use the light green lithium heparin gel tube, because the gel keeps the drug off the cells
• b.Avoid the lithium heparin tube, because the additive itself contains lithium✓
• c.Avoid the plain red tube, because glass activates and destroys lithium in the specimen
• d.Use the gray fluoride tube, because lithium is consumed by cells the way glucose is

A lithium heparin tube would add the very analyte being measured, so the reported concentration could be far above what the patient actually has and a real dose could be cut on the strength of it. A plain serum tube, or a sodium heparin tube where plasma is acceptable, avoids the problem. Glass does not destroy lithium, and lithium is not consumed by glycolysis, so a fluoride preservative has nothing to preserve.

In the standard order of draw, why is the green heparin tube collected before the lavender EDTA tube rather than after it?

• a.Heparin tubes clot faster than EDTA tubes, so they must be filled while the flow is best
• b.EDTA is supplied as a liquid additive and heparin as a spray-dried one, and liquids draw last
• c.Heparin carried into an EDTA tube destroys the white cells needed for a differential
• d.EDTA carried into a heparin tube would distort several chemistry and electrolyte results✓

The order of draw is arranged so that any additive dragged forward on the needle does the least harm. EDTA carried into a heparinised chemistry specimen raises potassium and lowers calcium, magnesium and alkaline phosphatase, so EDTA is placed after heparin rather than before it. Heparin carryover into an EDTA tube is undesirable but does not destroy white cells, and both additives can be supplied spray-dried.CLSI GP41

A stat basic metabolic panel is ordered on an inpatient. Why might the laboratory prefer a lithium heparin plasma tube over a gel serum tube?

• a.Plasma can be centrifuged as soon as it is mixed, while serum must clot first✓
• b.Plasma contains fibrinogen, and fibrinogen is required for accurate electrolyte measurement
• c.Serum tubes cannot be used at all for potassium, sodium, chloride or bicarbonate testing
• d.Plasma is drawn earlier in the order of draw, so the specimen spends less time on the needle

A serum tube has to be left upright long enough for the clot to form, typically about 30 minutes, before it can be spun. An anticoagulated plasma tube skips that wait entirely, which is why heparin tubes are common for stat chemistry. Plasma does contain fibrinogen, but that is a consequence of anticoagulation rather than a requirement for electrolytes, and serum is perfectly acceptable for a metabolic panel when time allows.

A phlebotomist fills a red clot activator tube first and then the light blue citrate tube for a PT/INR. What is the risk created by that sequence?

• a.Silica carried into the citrate tube dilutes the plasma and lowers every clotting factor
• b.Red tube additive has no effect on coagulation results because the red tube has no additive
• c.Clot activator carried forward can begin clotting and falsely shorten the clotting times✓
• d.The citrate tube will not fill after a serum tube because the vacuum has been used up

A red tube with clot activator is not additive-free. Silica particles dragged into a citrate tube start the very reaction the coagulation test is timing, so the plasma can clot faster than the patient truly would and an anticoagulated patient can look better controlled than they are. That is why the citrate tube is drawn before any serum tube. Carryover is a contamination problem, not a dilution problem, and each tube carries its own vacuum.CLSI GP41

How does the thixotropic gel in a serum separator tube do its job once the tube is centrifuged?

• a.It chemically bonds to the fibrin clot and drags the whole clot down to the bottom of the tube
• b.Its density lies between the cells and the serum, so it moves between the two layers✓
• c.It absorbs the serum and releases it slowly when the stopper is removed for testing
• d.It is heated by the friction of the spin and hardens into a plug across the tube

The gel is manufactured with a specific gravity between that of packed cells and that of serum. Under centrifugal force it becomes fluid, migrates to the position where those two densities meet, and sets there as a physical barrier that stops the cells from continuing to exchange potassium and glucose with the serum. It does not bond to fibrin, does not absorb serum, and does not depend on frictional heating.

The laboratory rejects a gel serum tube submitted for a therapeutic drug level and asks for a plain red tube instead. What is the usual reason for that policy?

• a.Gel tubes hold too little serum for the volume a drug assay needs to run in duplicate
• b.The clot activator in a gel tube chemically converts many drugs into inactive forms
• c.Drug levels must always be drawn into glass, and every gel tube is made of plastic
• d.Some drugs are absorbed by the gel, so the measured concentration drifts downward✓

Certain drugs, phenytoin and some tricyclic antidepressants among them, partition into the separator gel over time, so a level measured hours later can read lower than the patient's true concentration and prompt a dose increase that is not needed. Laboratories that see this specify a plain tube, and each laboratory publishes its own list. Volume, clot activator chemistry and the glass-versus-plastic question are not what drives the policy.

A pink stopper tube is ordered for a type and screen. What does that tube contain, and what is special about how it is labelled?

• a.Spray-dried EDTA, and it needs the collector's identification and the date and time✓
• b.Sodium citrate, and it is the one tube a facility may label at the nursing station later
• c.Lithium heparin, and it may be labelled from the requisition before the patient is seen
• d.No additive at all, and the blood bank supplies a pre-printed label for the armband

The pink blood bank tube is an EDTA tube, and it is the identification rather than the additive that most often causes harm. Blood bank policy requires the tube to be labelled at the patient's side with the patient identifiers plus who drew it and when, so a mistransfused unit can be traced. Labelling away from the patient, or before the draw, is exactly the practice that produces a wrong-blood-in-tube event.

Why does a laboratory require a royal blue stopper tube for a zinc or a lead level rather than an ordinary tube?

• a.The dark stopper colour shields the specimen from light that would break down the metal
• b.Royal blue tubes are manufactured to contain very little background trace metal✓
• c.The additive in a royal blue tube concentrates trace metals so low levels can be detected
• d.Royal blue tubes hold twice the volume that a trace element assay needs to run

Ordinary stoppers and tube walls contain enough trace metal to move a result that is reported in micrograms per decilitre, so a contaminated tube can turn a normal zinc into an abnormal one. Royal blue tubes are made under controlled conditions to keep that background as low as possible, and they come with EDTA, heparin or no additive depending on the test. Colour has no light-shielding role here, no tube concentrates an analyte, and volume is not the issue.

An erythrocyte sedimentation rate is ordered on a black stopper tube. What is distinctive about how that tube must be filled?

• a.It must be filled last so no additive from an earlier tube reaches it
• b.It is filled to any convenient level because the laboratory dilutes the blood again anyway
• c.It has a fixed blood to citrate ratio of four to one and must be filled to the line✓
• d.It is filled halfway on purpose to leave the air space the sedimentation column requires

The black sedimentation tube uses sodium citrate at a four to one ratio rather than the nine to one ratio of the light blue coagulation tube, and the dilution is part of the measurement. An underfilled or overfilled tube changes that dilution and moves the reported rate, so the fill line is not optional. The laboratory does not dilute again, no air space is required, and this tube is not simply the last one drawn.

A yellow stopper tube containing ACD solution is ordered. Which use is it intended for?

• a.DNA studies, HLA typing and parentage testing, which need viable cells✓
• b.Aerobic and anaerobic blood cultures drawn straight into a tube rather than into bottles
• c.Coagulation testing when the light blue citrate tube is unavailable from the supply room
• d.Trace element and toxicology work that would be spoiled by an ordinary stopper

Acid citrate dextrose preserves red cell viability and nuclear material, which suits it to HLA phenotyping, DNA studies and parentage testing. The other yellow tube, the sterile one, contains SPS and is the one used for culture, so the stopper colour alone does not identify the tube. ACD is not interchangeable with the coagulation citrate tube, whose ratio and concentration are different, and trace element work needs the royal blue tube.

The only tubes ordered are a green lithium heparin tube and a lavender EDTA tube. Which sequence is correct and why?

• a.Lavender then green, because the EDTA tube must be filled while the flow is still brisk
• b.Either order is acceptable, because carryover only matters when a citrate tube is involved
• c.Lavender then green, because a heparin tube tolerates carryover better than an EDTA tube
• d.Green then lavender, because EDTA carried into a heparin tube would alter the chemistry✓

The relative order of the standard tubes does not change when only some of them are ordered. Heparin comes before EDTA so that potassium-bearing, calcium-chelating EDTA is never dragged into the chemistry specimen. Flow rate is not a reason to reorder tubes, and carryover is not a coagulation-only problem, which is precisely why the sequence still applies with no citrate tube in the set.CLSI GP41

A phlebotomist has drawn a gold gel serum tube, a green heparin tube and a lavender EDTA tube. Which mixing pattern matches the manufacturer's usual instructions?

• a.Shake all three tubes briskly ten times so the additive reaches every part of the sample
• b.Invert each additive tube gently, about five times for the gel tube and eight for the others✓
• c.Invert only the lavender tube, since EDTA is the one additive that can settle out of solution over time
• d.Stand all three upright for two minutes and let the additive dissolve without any handling

Additive tubes are mixed by slow, complete end-over-end inversions immediately after filling, and manufacturers publish a count for each tube, commonly around five for a gel serum tube and eight to ten for heparin and EDTA. Shaking is what causes hemolysis and foaming, letting a tube stand allows microclots to form in an anticoagulant tube, and every additive tube needs mixing, not just the EDTA one.CLSI GP41

A coagulation study is the only test ordered and a winged blood collection set will be used. Why is a discard tube drawn first?

• a.To flush any residual disinfectant from the needle first
• b.To give the vein time to refill so the citrate tube can be filled without any interruption
• c.To fill the air-filled tubing, which would otherwise short-fill the citrate tube✓
• d.To let the phlebotomist confirm the colour of the blood before committing the real tube

The tubing of a winged set holds a small volume of air. If the citrate tube is the first one attached, that air occupies part of the tube's measured vacuum and the tube stops filling short of its line, which throws off the nine to one ratio and prolongs the reported clotting time. A discard tube absorbs the air first. The discard need not be a citrate tube, but it must be drawn before the coagulation specimen.CLSI GP41

A lavender EDTA tube for a complete blood count is filled to only half of its stated volume. What is the most likely effect on the count?

• a.Red cells shrink in the excess EDTA, so the hematocrit reads falsely low✓
• b.The white cell count reads falsely high because the cells are concentrated in less plasma
• c.The specimen is unaffected because EDTA is present in a large excess in every tube
• d.The platelets clump into large aggregates that the analyser counts as extra red cells

A half-filled EDTA tube leaves the tube's fixed dose of anticoagulant in half the intended blood volume. At that concentration EDTA draws water out of the red cells, so the cells occupy less space and the hematocrit and mean cell volume fall below the patient's true values while the mean cell hemoglobin concentration rises. A short-filled tube is a rejection, not a specimen to run and interpret.

A lavender tube is set down on the counter and mixed several minutes after collection instead of immediately. Which result is most likely to be reported incorrectly?

• a.Hemoglobin, which leaks from the cells into the plasma during the delay
• b.Mean cell volume, which rises steadily whenever mixing is postponed
• c.White cell count, because delayed mixing causes the neutrophils to disintegrate
• d.Platelet count, because platelets are consumed by the microclots that form✓

Clotting begins within seconds of blood entering the tube, and platelets are recruited into the earliest microclots. Delayed mixing therefore removes platelets from suspension and the analyser reports a count lower than the patient's true one, which can trigger an unnecessary hematology workup or a transfusion decision. Hemoglobin, mean cell volume and the white count are far less sensitive to a short mixing delay.

A serum glucose is collected in a gold gel tube and sits uncentrifuged at room temperature for three hours before testing. What happens to the glucose result?

• a.It rises, because the clot continues to release stored glucose into the serum
• b.It falls, because the blood cells keep metabolising glucose until the serum is separated✓
• c.It is unchanged, because the gel barrier blocks all cell metabolism from the moment of collection
• d.It becomes unreportable, because glucose degrades into a compound the analyser misreads

Cells in contact with serum or plasma continue glycolysis, and glucose falls at a rate usually quoted as several percent per hour at room temperature. A three hour delay can turn a genuinely normal glucose into an apparently low one, or hide a real hyperglycemia. The remedy is to separate the serum within the laboratory's stated limit, or to collect into a gray fluoride tube. The gel does nothing until the tube is spun.

A phlebotomist needs a discard tube before a coagulation draw and reaches into the tube drawer. Which choice is appropriate?

• a.A lavender EDTA tube, because it is the one most often overstocked
• b.A gray fluoride tube, because its additive cannot affect a coagulation measurement
• c.A plain tube with no additive, or a second citrate tube used only as the discard✓
• d.Any tube at all, because the discard is thrown away and never reaches the laboratory

The discard tube is attached to the same needle that will then fill the real citrate tube, so its additive can be carried forward. A non-additive tube, or another citrate tube, removes that risk. An EDTA or fluoride discard defeats the purpose, because traces of either can reach the specimen that is actually tested. The discard only needs to fill the tubing dead space, not to fill completely.CLSI GP41

Which pair of tests is correctly matched to the tube additive that the specimen requires?

• a.Hemoglobin A1c to EDTA and blood alcohol to sodium fluoride✓
• b.Blood alcohol to EDTA and hemoglobin A1c to sodium fluoride
• c.Hemoglobin A1c to sodium citrate and blood alcohol to lithium heparin
• d.Blood alcohol to sodium citrate and hemoglobin A1c to a clot activator only

Hemoglobin A1c is measured on whole blood, which needs an anticoagulant that preserves cells, so the lavender EDTA tube is standard. Blood alcohol is collected into a tube that stops both glycolysis and microbial fermentation, which is the gray sodium fluoride tube, and the site is cleaned with a non-alcohol antiseptic. Citrate dilutes the specimen and is reserved for coagulation and sedimentation work.

A patient needs blood cultures, a CBC and a potassium level. The phlebotomist can only obtain one small vein. How should the draw be planned?

• a.Draw the CBC first so the most commonly ordered test is certain to be collected
• b.Draw the potassium first, since an electrolyte is the result the provider will act on soonest
• c.Combine all three tests into one lavender tube and let the laboratory divide the sample
• d.Keep the standard order, cultures first, and get a second site if the vein cannot supply all✓

A limited vein does not change which additive can ruin which test, so the sequence stays as it is: sterile culture bottles, then the chemistry tube, then the EDTA tube. If the vein will not yield everything, the answer is a second site or a second attempt within policy, not a reshuffle. Tests cannot be run from the wrong additive, so pooling all three into one EDTA tube would make the potassium and the cultures unusable.CLSI GP41

A rapid serum tube containing thrombin is available on the unit. What advantage does it offer over a standard gel serum tube?

• a.The specimen clots in a few minutes rather than the usual half hour✓
• b.It removes the need to invert the tube after collection, saving a step at the bedside
• c.It yields plasma instead of serum, so fibrinogen can be measured from the same tube
• d.It can be centrifuged while it is still filling, which shortens the total handling time

Thrombin drives fibrin formation directly, so the tube completes clotting in roughly five minutes and can be spun almost immediately, which suits stat chemistry. It still requires the manufacturer's inversions, it still yields serum rather than plasma, and no tube may be centrifuged before it is filled, closed and mixed.

A phlebotomist is choosing a needle for a routine adult antecubital draw with an evacuated tube system. What does a higher gauge number mean?

• a.A longer shaft, so a 23 gauge reaches deeper veins than a 21 gauge
• b.A smaller bore, so a 23 gauge needle is narrower than a 21 gauge needle✓
• c.A thicker wall on the same bore, which makes the higher gauge sturdier for difficult veins
• d.A wider bore, so a 23 gauge draws faster and is preferred whenever the veins are fragile

Gauge counts inversely to diameter: as the number rises the lumen narrows. A 21 gauge is the usual routine adult choice, a 22 gauge suits smaller veins, and a 23 gauge is typical of a winged set. Gauge says nothing about length, which is specified separately, and a narrower bore slows flow rather than speeding it, which is one reason very high gauges raise the risk of hemolysis.CLSI GP41

Where should the tourniquet be placed for an antecubital venipuncture, and how long may it stay on?

• a.Directly over the intended puncture site, and it may remain until the last tube has filled
• b.At the wrist, so the veins of the forearm and the antecubital fossa both fill at the same time
• c.Three to four inches above the intended site, and for no longer than one minute✓
• d.Over the shoulder, and it must be left in place for at least two minutes to distend the vein

The tourniquet goes roughly three to four inches, or about seven to ten centimetres, proximal to the intended site, over clothing or a gauze pad if the skin is fragile. It should be released within one minute, because longer application produces hemoconcentration that raises protein, calcium, iron and cell counts. If more time is needed to find a vein, take the tourniquet off for two minutes and reapply it once the site has been selected.CLSI GP41

How should a phlebotomist anchor the vein just before inserting the needle?

• a.Draw the skin taut with the thumb one to two inches below the intended site✓
• b.Place the index finger above the site and the thumb below it, gripping the arm from both sides
• c.Press directly over the vein with two fingers so it cannot roll away from the advancing needle
• d.Squeeze the forearm with the free hand throughout the draw to keep the vein filled and firm

Pulling the skin taut distal to the site fixes the vein without putting any part of the phlebotomist's hand in the needle's path. The two-finger grip that straddles the site places a finger above the puncture, which is where the needle travels if the patient jerks, and it has produced real needlestick injuries. Pressing on the vein itself flattens it, and squeezing the forearm causes hemoconcentration.CLSI GP41

A blood collection has just finished. What must happen to the needle and the evacuated tube holder?

• a.Recap the needle using a one-handed scoop technique, then place the capped needle in the sharps bin
• b.Unscrew the needle into the sharps container and wipe the holder with disinfectant for reuse
• c.Cut the needle from the holder with a needle cutter so it cannot be picked up and reused
• d.Activate the safety device and discard the needle and holder together as one unit✓

The safety feature is engaged immediately, before the device leaves the patient's side, and the needle stays attached to the holder so that no one has to handle a contaminated hub. Reusing a holder exposes the next patient and the next worker to the blood left in it, and detaching a used needle is an extra handling step the standard is written to avoid. Recapping and needle cutting are both prohibited practices.OSHA 29 CFR 1910.1030

Blood was collected into a syringe because the patient's veins were fragile. How should the tubes be filled?

• a.Remove each stopper and pour the blood in, replacing the stopper as soon as the tube is filled
• b.Attach a blood transfer device and let each tube fill under its own vacuum✓
• c.Push the syringe needle through each stopper and depress the plunger until the tube looks full
• d.Fill the additive tubes first and put whatever blood is left over into the plain non-additive tube

A transfer device seats the syringe on a shielded holder so the tubes draw their own volume, which controls the fill and keeps the phlebotomist's hands away from the needle. Forcing blood through a needle into a stoppered tube pressurises the tube, hemolyses the sample and is a recognised needlestick hazard. Pouring destroys the closed system. Tubes are filled in the standard order of draw whatever the collection method.CLSI GP41

A routine venipuncture is being completed. Which statement must be true of the finish?

• a.The needle is withdrawn first and the tourniquet released once the needle is out
• b.Pressure is applied to the puncture site while the needle is still inside the vein
• c.The tourniquet is off and the last tube out before the needle is withdrawn✓
• d.The patient bends the elbow over the gauze instead of holding steady pressure

Two things are true before the needle comes out: the tourniquet is off, so the vein is not under pressure at the moment it is opened, and the last tube is out of the holder, so whatever vacuum it has left cannot pull blood back through the needle. Pressure goes on after the needle is out rather than while it is still in the vein, and bending the elbow instead of holding pressure is a well known cause of hematoma.CLSI GP41

A phlebotomist palpates a structure in the antecubital fossa. Which finding indicates a vein rather than a tendon or an artery?

• a.It feels soft and springy and rebounds under the fingertip when it is released✓
• b.It feels hard and cord-like and does not move at all when it is pressed from the side
• c.It produces a distinct rhythmic beat under the finger
• d.It is visible as a blue line but cannot be felt at all when the site is palpated firmly

A vein has a bouncy, resilient feel and springs back when released. A tendon is firm and cord-like and does not give. An artery pulses, and puncturing one produces bright red pulsating flow that needs firm prolonged pressure and a report. Choosing a vein by appearance alone is unreliable, which is why a vein that can be seen but not felt is not a safe first choice.

The needle is in the vein, a flash appears, and then the tube stops filling almost immediately. What should the phlebotomist try first?

• a.Withdraw the needle completely and start again in the opposite arm without any further attempt
• b.Probe from side to side with the needle tip until blood returns
• c.Pull the plunger of a syringe hard enough to overcome whatever is blocking the flow
• d.Try a fresh tube, since a tube that has lost its vacuum will not fill at all✓

A tube that has lost its vacuum, through a manufacturing fault or an accidental partial engagement, is the simplest and most common explanation for a good flash followed by no fill. Changing the tube costs nothing and risks nothing. Lateral probing is prohibited because it causes nerve injury, hematoma and severe pain, and forcefully aspirating with a syringe collapses the vein and hemolyses the specimen.CLSI GP41

Two venipuncture attempts on the same patient have failed. What does standard practice call for next?

• a.A third attempt at the same site using a larger gauge needle
• b.Stop, and ask another phlebotomist to take over or notify the requesting nurse or provider✓
• c.Switch to a heel stick, which is an acceptable substitute for a venous draw in any adult patient
• d.Keep attempting until the specimen is obtained, since a missing result delays the patient's care

Two unsuccessful attempts is the customary limit, after which the collection is handed to a colleague or referred back to the ordering nurse or provider. The number is a professional norm and some employers set their own limit, so follow local policy. A larger needle does not fix a technique or access problem, and heel sticks are a neonatal and infant procedure, not an adult alternative.CLSI GP41

Which collection practice is most likely to hemolyze a specimen and cause the laboratory to reject it?

• a.Filling the tubes in the standard order of draw and inverting each one immediately
• b.Letting the alcohol dry completely before the needle is inserted into the prepared site
• c.Drawing through a needle that is too small for the tube's vacuum and shaking the tube✓
• d.Choosing the median cubital vein rather than a vein on the back of the patient's hand

Red cells rupture when they are forced through a narrow lumen or agitated, so a very high gauge needle paired with a large evacuated tube, plus vigorous shaking, is a reliable way to hemolyze a sample. Drawing before the alcohol dries also contributes. The order of draw, prompt gentle inversion and the choice of the median cubital vein are all correct practices that protect the specimen.

How should the needle be oriented and advanced during an antecubital venipuncture?

• a.Bevel up, running in the same direction as the vein, and at a shallow angle✓
• b.Bevel down, so the sharpest edge of the needle is against the floor of the vein as it enters
• c.Bevel up but across the vein at a right angle, so the lumen is entered at its widest point
• d.Bevel to the side, entering at roughly forty five degrees so the vein cannot roll out of the way

The bevel faces up and the needle follows the line of the vein at a shallow angle, generally described as fifteen to thirty degrees for an antecubital site. A bevel turned down can occlude against the vessel wall and stop the flow. Crossing the vein at a right angle or entering at a steep angle drives the needle through the far wall, which produces a hematoma and a failed draw.CLSI GP41

A patient's vein collapses as the second tube begins to fill. Which adjustment is appropriate?

• a.Increase the pull by attaching the largest evacuated tube available in the tray
• b.Push the needle in deeper, because a collapsed vein means the needle has not gone far enough
• c.Ask the patient to pump the fist vigorously until the vein refills and the flow returns
• d.Switch to a smaller tube or a winged set, which applies less vacuum to the vein✓

A small or fragile vein collapses when the vacuum pulling on it exceeds what it can supply, so the fix is to reduce that vacuum with a smaller tube, a winged set or a syringe. A larger tube pulls harder and makes it worse. Advancing the needle risks going through the far wall, and vigorous fist pumping raises potassium and lactate in the specimen without solving the problem.

Why must the patient's arm be held downward and the tubes kept below the puncture site during a draw?

• a.Because gravity is what pulls the blood out of the vein and into the evacuated tube
• b.To keep tube contents from flowing back along the needle into the patient's vein✓
• c.Because the tubes will not engage on the holder correctly if they are held above the arm
• d.To let the phlebotomist read each label from above while the tube is still filling with blood

If a tube is raised above the puncture site, its contents can travel back down the needle and reach the patient. That reflux can carry additive into the bloodstream and, historically, has transmitted contamination between tubes. Keeping the arm in a downward position with the tubes below the site prevents it. The vacuum, not gravity, moves the blood, and tube engagement does not depend on height.CLSI GP41

After the needle is removed, how should the phlebotomist manage the puncture site on a patient who is not taking an anticoagulant?

• a.Have the patient bend the elbow tightly over the gauze, which is faster than holding pressure
• b.Apply the bandage at once and let the pressure of the adhesive stop the bleeding by itself
• c.Hold firm pressure with gauze until bleeding stops, then bandage the arm✓
• d.Wipe the site clean with alcohol and rub it briskly to close the puncture in the vein wall

Direct pressure with the arm extended is what closes the puncture. Bending the elbow reopens the vessel and is a classic cause of hematoma. A bandage applied over a site that is still bleeding traps blood under the skin rather than stopping it. Rubbing the site with alcohol disturbs the forming plug and can restart the bleeding. Patients on anticoagulants need pressure held noticeably longer.

A phlebotomist has cleaned an antecubital site with alcohol and can no longer see the vein clearly. What is the correct response?

• a.Palpate the vein again with an ungloved fingertip, since gloves reduce the sense of touch
• b.Repalpate above or below the cleaned area, or clean the site again if the area is touched✓
• c.Insert the needle where the vein was last seen and adjust the angle once a flash appears
• d.Wait for the alcohol to dry, then rub the cleaned skin with a dry gauze to raise the vein again

Once the site is prepared it must stay clean, so any palpation happens outside the prepared area, and touching the prepared skin means cleaning it again before puncture. Gloves are required and are never removed for palpation. Guessing at a remembered position leads to probing, and rubbing prepared skin with gauze recontaminates it and irritates the site.

An outpatient tells the phlebotomist that she always faints during blood draws. What is the safest way to position her?

• a.Seat her on a stool without a backrest so she can be moved quickly if she starts to fall
• b.Have her stand facing the phlebotomist, which shortens the distance if she needs to sit down
• c.Seat her on the edge of an examination table with her legs hanging
• d.Place her in a reclining position or a phlebotomy chair with a locking armrest✓

A patient with a history of syncope is drawn reclining, or in a chair whose armrest locks across the front so she cannot slump forward and fall out. A backless stool, a standing patient and a perched position on a table edge all end with an unsupported fall if consciousness is lost. The phlebotomist also stays with the patient afterwards rather than leaving immediately.

A hematoma begins to form and the site swells while the second tube is filling. What should the phlebotomist do?

• a.Release the tourniquet, withdraw the needle and apply firm pressure to the site✓
• b.Continue the draw quickly and apply an ice pack once every ordered tube has been collected
• c.Leave the needle in place and press hard on the swelling to force the blood back into the vein
• d.Loosen the tourniquet slightly and reposition the needle a little deeper to find the vein again

A swelling means blood is leaking into the tissue, and every second the needle stays in adds to it. The draw is stopped, the tourniquet released, the needle withdrawn and firm pressure applied, and cold may be offered afterwards. Finishing the tubes first, pressing on the site with the needle still in, or repositioning the needle all enlarge the hematoma and increase the risk of nerve compression.

A patient's antecubital veins are unusable and the phlebotomist considers a vein on the back of the hand. What is the appropriate approach?

• a.Hand veins are prohibited in adults and the draw must be cancelled and returned to the provider
• b.Use the same 21 gauge needle and full size tube, because the site does not change the equipment
• c.Use a winged set with a smaller gauge and smaller tubes, and anchor the fragile vein carefully✓
• d.Draw from the underside of the wrist instead, where the veins are straighter and easier to see

Dorsal hand veins are an accepted alternative when the antecubital fossa cannot be used, but they are small and superficial, so a winged set, a higher gauge and small volume tubes are appropriate and the skin needs careful anchoring. The underside of the wrist is specifically avoided because of the nerves and arteries lying close to the surface there.

Why does the basilic vein carry more risk than the median cubital vein even when it is the easiest one to see?

• a.It lies deeper than the other antecubital veins and needs a much steeper angle of entry
• b.The median nerve and the brachial artery both lie close beside that vein✓
• c.It collapses under normal tube vacuum far more readily than the cephalic vein does
• d.It carries arterial rather than venous blood, so any specimen from it is unsuitable for testing

The basilic vein sits on the medial side of the antecubital fossa, where the median nerve and the brachial artery are nearby, so a misdirected needle can cause nerve injury or arterial puncture. That is why it is the last of the three choices even when it looks inviting. It carries venous blood like any other vein, and depth and collapse are not what make it the last resort.

A patient asks the phlebotomist to draw from a vein in the ankle because the arm veins are difficult. What should the phlebotomist do?

• a.Agree, because ankle veins are treated exactly like arm veins under standard collection policy
• b.Agree only if the patient signs a written consent form describing the risks of the site
• c.Refuse and cancel the order, since a lower extremity may never be used for a blood draw
• d.Explain that lower extremity sites need provider approval, and obtain it before drawing✓

Foot and ankle punctures carry a higher risk of thrombosis and of poor healing, particularly in patients with diabetes or vascular disease, so most facilities require the ordering provider's approval before a phlebotomist uses one. They are neither routine nor absolutely forbidden. A patient's own consent does not replace the approval, and cancelling the order is not the phlebotomist's decision to make alone.

A patient receiving hemodialysis has an arteriovenous fistula in the left forearm. What does that mean for the blood draw?

• a.Do not use that arm without the provider's permission; use the other arm✓
• b.The fistula itself provides the easiest access and should be punctured whenever a vein is hard to find
• c.The arm may be used freely below the fistula as long as a tourniquet is never applied to it
• d.Only capillary collection is permitted anywhere on a patient who receives regular hemodialysis

A fistula is the patient's dialysis lifeline, and a puncture or an infection in that arm can cost them the access. Phlebotomists do not puncture a fistula, and the arm carrying it is avoided altogether unless the provider says otherwise, so the opposite arm is used. Dialysis by itself does not restrict a patient to capillary collection everywhere on the body.

The only accessible vein is below an intravenous line that is currently infusing. What is the accepted practice?

• a.Draw above the running line, since blood flows toward the heart and the fluid moves away from it
• b.Draw from the line itself after clamping it, because that avoids a second needle stick entirely
• c.Ask the nurse to stop the infusion, wait two minutes, draw below it and discard the first tube✓
• d.Draw below the line while it is still running and simply note the infusion on the requisition

When no other site is available, the infusion is stopped by the nurse, a short wait allows the fluid already in the vein to clear, the puncture is made distal to the line, a discard volume is taken and the situation is documented. Drawing above a running line samples the infusion itself and produces grossly wrong glucose, potassium and electrolyte results. Drawing from the line is a nursing procedure, not a phlebotomy one.

Which patient finding should make a phlebotomist choose a different arm before applying the tourniquet?

• a.A small freckle or a mole several inches away from the antecubital fossa on that arm
• b.Extensive scarring from a burn across the whole antecubital area of that arm✓
• c.A faded tattoo on the upper arm well above where the tourniquet would be placed
• d.A blood pressure cuff that was used on that arm and removed about ten minutes earlier

Burned or heavily scarred tissue has poor circulation, is difficult to puncture, is painful and carries a higher infection risk, so the site is avoided. Edema, hematoma and sclerosed veins are avoided for the same reasons. A freckle, a healed tattoo away from the site, and a blood pressure cuff already removed do not compromise the specimen or the patient.

A phlebotomist warms a patient's arm with a commercial warming pack before a difficult draw. What is the purpose and the limit?

• a.Warming thins the blood so it flows faster, and any temperature the patient can tolerate is fine
• b.Warming sterilises the skin surface, so the alcohol prep can then be shortened to a single wipe
• c.Warming dilates the vessels to improve flow, and the pack should stay near 42 degrees Celsius✓
• d.Warming is used only on infants and has no accepted role in an adult venipuncture at any site

Heat causes local vasodilation and increases blood flow to the site, which makes a small vein easier to enter and a capillary collection easier to complete. The commonly cited ceiling is about 42 degrees Celsius, roughly 108 degrees Fahrenheit, applied for three to five minutes, because hotter packs burn skin, especially an infant's. Warming does not sterilise anything and does not change blood viscosity.

A patient tells the phlebotomist that latex gives her a rash and makes her wheeze. What should the phlebotomist do?

• a.Use a latex-free tourniquet, gloves and bandage, and document the allergy✓
• b.Use the usual latex tourniquet but place it over the sleeve so that it never touches her skin
• c.Use latex gloves and a latex tourniquet quickly, since a brief contact is too short to cause a reaction
• d.Send the patient away to obtain a written allergy statement from her provider before drawing

Wheezing is a systemic symptom, so this is treated as a genuine latex allergy and every item that touches the patient is latex-free, including the tourniquet, gloves and any adhesive bandage. Barriers and brief contact are not reliable protection, and airborne powder from latex gloves can trigger symptoms. There is no reason to delay the draw for paperwork the patient does not need.

A phlebotomist is asked to collect blood from a patient who is having a seizure at the moment of arrival. What is the correct action?

• a.Draw quickly from the arm that is moving least, because a stat order cannot be delayed for any reason
• b.Do not attempt the draw; get help, protect the patient from injury and return when it is safe✓
• c.Hold the patient's arm firmly still with the help of a colleague and complete the collection
• d.Place a padded tongue blade between the teeth first, then decide whether the draw can proceed

A needle must never be introduced into a moving limb, and no laboratory result is worth a nerve injury or a needlestick. The phlebotomist summons help, keeps the patient from striking nearby objects and does not restrain them, then returns once the seizure has ended and the nurse confirms it is safe. Putting anything into the mouth of a seizing patient is an outdated practice that causes injury.

Which area of a newborn's foot is an acceptable heel puncture site?

• a.The posterior curvature of the heel, where the skin is thickest and the stick hurts least
• b.The medial or lateral plantar surface of the heel, away from the curve of the bone✓
• c.The centre of the arch, because it is the fleshiest part of the sole
• d.Any part of the sole, provided the lancet used is a retractable safety model

The plantar surface medial or lateral to an imaginary line drawn back from the great toe and from between the fourth and fifth toes keeps the lancet away from the calcaneus. The posterior curvature sits directly over that bone, and the arch overlies nerves, tendons and arteries. A safety lancet controls depth but does not make an unsafe location safe.CLSI GP42

What is the maximum penetration depth accepted for a heel puncture on a newborn, and why does it matter?

• a.Five millimetres, which is needed to reach the capillary bed under an infant's thick plantar skin
• b.Whatever depth the device delivers, since incision devices are pre-set by the manufacturer
• c.Two millimetres, because a deeper stick can reach the bone and cause osteomyelitis✓
• d.One centimetre, matching the depth used for an adult fingerstick

The accepted ceiling is 2.0 millimetres. The calcaneus of a newborn lies close beneath the plantar skin, and a lancet that reaches it can cause bone infection, cartilage damage and scarring. Devices are indeed pre-set, but the phlebotomist still has to choose one made for a newborn heel rather than one made for an adult finger, so the depth limit is the reason the choice matters.CLSI GP42

Which finger and which part of it should be used for an adult capillary puncture?

• a.The fleshy pad of the third or fourth finger, slightly off centre and across the fingerprint lines✓
• b.The thumb, because it has the largest blood supply of any digit and therefore bleeds the most freely
• c.The very tip of the index finger, which is the easiest point to reach with a lancet
• d.The side of the fifth finger, where the tissue over the bone is thinnest

The middle or ring finger of the non-dominant hand is punctured on the palmar side of the last joint, just to the side of centre, and the cut is made across rather than along the fingerprint lines so the drop forms instead of running into a groove. The index finger and thumb are more callused and more used, the little finger has too little tissue over bone, and the very tip and the sides are more painful and poorly perfused.CLSI GP42

Why is the first drop of blood wiped away after a capillary puncture?

• a.Because it is the coldest blood in the finger and would give a falsely low glucose reading
• b.Because it has already begun to clot and would block the microtube before it could be filled
• c.Because wiping it is the only way to remove the alcohol from the puncture
• d.Because it is diluted with tissue fluid, and residual alcohol may be mixed into it as well✓

The puncture releases interstitial fluid along with blood, and any alcohol that has not fully evaporated is carried in the same first drop. Both dilute the specimen and can hemolyze it, so that drop is wiped away with clean gauze and collection begins with the second. Blood does not clot that quickly, and temperature has no bearing on it. Letting the alcohol dry before puncturing is a separate and equally necessary step.CLSI GP42

A capillary specimen is filling slowly, so the phlebotomist squeezes the finger repeatedly. What is the consequence?

• a.The specimen fills faster with no effect on the result, which is why the technique is widely taught
• b.Tissue fluid and hemolysis contaminate the specimen and distort potassium and cell counts✓
• c.The specimen clots faster because squeezing activates the platelets in the puncture wound
• d.Nothing changes, because the microtube additive corrects for any dilution that occurs

Milking forces interstitial fluid into the sample and ruptures red cells, which raises potassium and lowers cell counts and can make a normal potassium look dangerously high. The remedy for slow flow is to warm the site beforehand, hold the hand below heart level and apply gentle intermittent pressure well behind the puncture, or to repuncture at a new site. No additive corrects contamination that is already in the tube.CLSI GP42

In what order are capillary microcollection containers filled when several are required?

• a.Serum first, then the additive tubes, mirroring the venous order of draw exactly as written
• b.The largest container first, so the best quality blood goes where the most volume is needed
• c.Blood gas specimens first, then EDTA, then other additive tubes, then serum✓
• d.Any order, because a capillary sample is mixed continuously as it drips into each container

The capillary order differs from the venous one. EDTA comes early, immediately after any blood gas specimen, because platelets begin to aggregate at the puncture site and a delayed EDTA tube gives a falsely low platelet count. Serum containers come last. Container size does not determine the sequence, and the order is not optional because the changes happen in the wound, not in the tube.CLSI GP42

How does capillary blood differ chemically from venous blood drawn at the same moment?

• a.Glucose runs higher, while potassium, calcium and total protein all run lower✓
• b.Every analyte is identical, because capillary blood is simply venous blood collected from a smaller vessel
• c.Glucose runs lower and potassium runs higher, so a capillary potassium may be reported as critical
• d.Only the cell counts differ; all of the chemistry values are the same in both specimens

A skin puncture yields a mixture of arterial, venous and capillary blood together with interstitial and intracellular fluid, and the arterial contribution raises glucose while potassium, calcium and total protein come out lower than a venous specimen. The differences are real and predictable, which is why a laboratory records the source and why capillary and venous results should not be compared as if identical.

A newborn screening card is being collected by heel stick. Which technique produces an acceptable specimen?

• a.Touch the card repeatedly to the heel until each printed circle looks evenly and completely coloured
• b.Layer several small drops on top of one another until it is saturated
• c.Fill the circles from the back of the card, since the printed side is treated and repels blood
• d.Let one large drop soak through and fill each circle, applying blood to one side only✓

Each circle is filled with a single large free-falling drop applied to one side of the filter paper and allowed to soak through, then the card is air dried horizontally at room temperature away from heat and sunlight. Repeated touching, layering and applying blood to both sides all produce clotted, layered or saturated spots that the screening laboratory rejects, which delays the detection of a treatable metabolic disorder.

Why should povidone iodine not be used to prepare the skin for a capillary puncture?

• a.It stains the skin, which makes it impossible to see the puncture site clearly enough to collect
• b.Iodine carried into the sample falsely raises potassium, phosphorus and uric acid✓
• c.It takes far longer to dry than alcohol, and the collection cannot begin until it has dried
• d.It is reserved for blood cultures, and using it elsewhere wastes an expensive supply

Iodine residue picked up in a skin puncture specimen interferes with several chemistry measurements and can push a result out of range on its own, so seventy percent isopropyl alcohol is used for routine capillary work and allowed to dry completely. Drying time and cost are real considerations but they are not the reason, and blood cultures are one of several appropriate uses for iodine.

Why is a fingerstick avoided in an infant under one year of age?

• a.Infants under one year have no measurable capillary circulation in the fingers at all
• b.The fingers of an infant cannot be warmed enough to produce a usable flow of blood
• c.There is too little tissue between the skin and the bone, so the lancet can injure it✓
• d.The volume obtainable from an infant finger is always far greater than a microtube can hold

The distance from skin to bone in an infant's finger is small enough that a lancet set for an adult finger can reach the phalanx, so the heel is used instead until the child is walking and the plantar tissue thickens. Infants certainly have capillary circulation and their fingers can be warmed. Yield is a limitation of the site, not an overflow problem.

A neonatal bilirubin is collected by heel stick into a microtube. What handling does the specimen require?

• a.Warm the microtube to body temperature and deliver it to the laboratory within four hours
• b.Freeze the specimen at once, because bilirubin breaks down rapidly at any warmer temperature
• c.Add a drop of saline to the microtube so the small volume can be pipetted by the analyser
• d.Protect it from light and deliver it promptly, using an amber tube or a foil wrap✓

Bilirubin is degraded by light, and a specimen left on a windowsill or under a phototherapy lamp can lose a clinically important amount within an hour. That falsely low result may mask a rising bilirubin in a newborn at risk of kernicterus. The tube is shielded and sent straight to the laboratory. Warming, freezing and diluting a specimen are not part of bilirubin handling.

Which statement about drawing blood from a premature or low birth weight infant is correct?

• a.The total volume removed must be tracked, because repeated draws can cause iatrogenic anemia✓
• b.Volume is not a concern, since an infant regenerates blood a great deal faster than an adult does
• c.The infant should be drawn from a single site each time so that only one area ever bruises
• d.The heel may be punctured as many times as needed provided a new lancet is used each time

A small infant has a very small circulating volume, so millilitres removed for testing matter and neonatal units set cumulative limits over a defined period. Sites are rotated rather than reused, because repeated punctures in one place cause scarring and infection. A fresh lancet is required every time but that does not license unlimited punctures.

A four-year-old is frightened and asks the phlebotomist whether the blood draw will hurt. What is the best reply?

• a.Reassure the child that it will not hurt at all, so that she relaxes and holds still for the needle
• b.Say honestly that it will pinch for a moment, and give her something simple to do during it✓
• c.Explain the venipuncture procedure step by step in the same detail used for an adult patient
• d.Tell her that children who cry during a blood draw have to be held down by two people

Children cope better with a short honest description and a small task, such as counting or holding a parent's hand, than with a promise that is broken the moment the needle enters and destroys their trust for every future draw. Adult-level detail overwhelms a preschooler, and threatening restraint is coercive and increases distress rather than reducing it.

Why are adhesive bandages generally avoided on children under two years old after a blood collection?

• a.Because the adhesive prevents the puncture from clotting and the child will keep bleeding
• b.Because a bandage hides the site from the parent afterwards
• c.They can be pulled off and swallowed, and the adhesive tears very delicate skin✓
• d.Because a toddler's skin is too oily for any adhesive dressing to stay in place at all

A small child will pick at a bandage, and a loose one is a choking hazard, while the adhesive itself can strip the thin skin of an infant. Pressure is held until bleeding stops and gauze secured with a self-adherent wrap is used if a covering is needed. Adhesive does not stop a clot forming, and hiding the site is a minor issue next to aspiration.

An 82-year-old patient has thin, papery skin and prominent but fragile veins. Which set of adjustments is appropriate?

• a.Apply the tourniquet more tightly than usual so the fragile vein is held firmly in position
• b.Use the largest tube available so the draw finishes before the vein has time to collapse
• c.Slap the skin over the vein to raise it, then insert quickly at a steep angle
• d.Use a winged set and small tubes, anchor gently, and hold pressure for longer afterwards✓

Fragile veins tolerate less vacuum and fragile skin tolerates less traction, so a winged set with small volume tubes, gentle anchoring and unhurried entry protect both. Pressure is held longer because older patients bleed longer, particularly on aspirin or an anticoagulant. A tighter tourniquet, a larger tube and slapping the skin all increase the risk of hematoma and skin tearing.

How should a phlebotomist secure the puncture site on an older patient whose skin tears easily?

• a.Hold gauze with pressure, then wrap it with a self-adherent bandage instead of adhesive tape✓
• b.Apply a strong adhesive tape and warn the patient to pull it off quickly in a single movement
• c.Skip any covering, since older skin heals fastest when the site is left completely open
• d.Use two adhesive bandages crossed over one another so the gauze cannot slip out of place

Self-adherent wrap sticks to itself rather than to skin, so it holds gauze in place without stripping tissue when it comes off. Adhesive tape on paper-thin skin can tear it and open a wound that heals slowly. Leaving the site uncovered risks bleeding restarting, and doubling adhesives multiplies the very problem being avoided.

A phlebotomist is drawing blood from a patient with advanced dementia who does not respond to questions. How should identification be handled?

• a.Accept the room number and the name written on the door as the two required identifiers
• b.Verify the wristband against the requisition and have a caregiver or nurse confirm the identity✓
• c.Ask the patient to state her own name and accept whatever answer she gives without any further checking
• d.Draw the specimen first and confirm the identity with the nurse before the label is applied

A patient who cannot reliably state her own name is identified from the wristband checked against the requisition, with a nurse, caregiver or family member confirming. Room numbers and door signs are not patient identifiers and change constantly. Accepting an unreliable verbal answer, or labelling after the fact, are the two routes to a wrong-patient result and a wrong transfusion.

Which microhematocrit tube should be used to fill directly from a capillary puncture with no anticoagulant tube in between?

• a.The tube with a blue band, which contains no additive at all
• b.Either tube, because the sample spins down to the same packed cell volume in both cases
• c.The tube with a red band, which is coated on the inside with heparin✓
• d.Neither, because a hematocrit can only be run from a venous lavender tube

Blood taken straight from a skin puncture has nothing to stop it clotting, so the heparinised tube, marked with a red band, is the correct choice. The blue banded plain tube is used when the blood has already been anticoagulated, typically from a lavender EDTA tube. A clotted specimen gives a meaningless packed cell volume, and hematocrit is routinely performed on capillary blood.

A parent asks to hold her two-year-old during a venipuncture. What is the usual practice?

• a.Parents are excluded from the room so that their anxiety cannot transfer to the child
• b.The parent may stay only if she agrees to hold the arm still while the needle is inserted
• c.The child must be swaddled alone on a table, because any holding contaminates the site
• d.A supportive hold with the parent present is encouraged where facility policy allows it✓

Comfort positioning, with the child upright on the parent's lap and the arm supported, reduces distress and struggling and is widely encouraged where policy permits. Excluding a parent is not the norm, and asking a parent to restrain a child places them in the role the child will remember. Being held does not contaminate a site that is prepared and kept clean.

How long should a heel warming device be applied before a newborn capillary collection, and at what temperature?

• a.Three to five minutes at a temperature no higher than about 42 degrees Celsius✓
• b.Fifteen to twenty minutes at whatever temperature the nursery warmer happens to be set to
• c.Thirty seconds at 50 degrees Celsius, which opens the capillaries fastest of all the options
• d.Warming is not used on newborns because their circulation is already at its maximum

Three to five minutes of gentle warming at a ceiling of about 42 degrees Celsius increases blood flow to the heel several fold and makes a single puncture sufficient. Hotter packs scald infant skin, which is thinner than an adult's. A quarter of an hour is unnecessary and leaves the infant handled longer than needed, and warming is a standard part of neonatal capillary collection.

Which specimen should not be collected by skin puncture?

• a.A hemoglobin and hematocrit on a patient whose veins are exhausted from repeated draws
• b.A set of blood cultures on a patient with a suspected bloodstream infection✓
• c.A point of care glucose on a patient in an outpatient diabetes clinic
• d.A newborn screening card on a two-day-old infant in the nursery

Blood cultures need a volume that a skin puncture cannot supply, and the puncture site cannot be kept sterile through a capillary collection, so contamination and false negatives follow. Point of care glucose, newborn screening and small volume hematology are all standard capillary work. Tests requiring plasma or serum in quantity, and coagulation studies, are also unsuitable.

A capillary glucose is collected from a patient's fingertip immediately after the patient has eaten an orange without washing their hands. What is the risk?

• a.Citric acid on the skin destroys the glucose in the sample and the meter will read far too low
• b.There is no risk, because the meter measures only what it draws in
• c.Sugar residue on the finger can be picked up in the drop and give a falsely high glucose✓
• d.The fruit acid corrodes the test strip so the meter displays an error rather than a number

Contamination from food, juice, lotion or an alcohol-based hand product on the fingertip is a documented cause of falsely high point of care glucose readings, and a spuriously high result can prompt an insulin dose the patient does not need. The site is washed with soap and water and dried before the puncture. Meters measure glucose in whole blood, not only inside cells.

A phlebotomist runs the low and high control solutions on a point of care glucose meter and the high control falls outside its range. What is the correct action?

• a.Do not report patient results from that meter; troubleshoot and repeat before any patient is tested✓
• b.Report the patient results but add a comment noting that the high control was out of range that morning
• c.Run only the low control from then on, since it was the one that gave an acceptable result
• d.Test the patient anyway and repeat the control afterwards to see whether it corrects itself

A failed control means the instrument has not demonstrated that it can measure accurately, so patient testing stops until the cause is found, whether it is an expired strip lot, a storage problem, a coding error or the meter itself. Reporting with a comment, dropping a control level or testing first and checking later all put a patient result of unknown accuracy into the record.

A patient at an outpatient clinic needs a hemoglobin A1c and has excellent antecubital veins. Why is a venous draw usually preferred over a capillary one here?

• a.Capillary blood cannot be used for a hemoglobin A1c under any circumstances at all
• b.A venous specimen gives adequate volume and avoids the tissue fluid a skin puncture adds✓
• c.Capillary punctures are more painful than venipuncture, so patients refuse them more often
• d.A capillary sample would clot immediately because no microtube contains a suitable additive

Where a good vein is available, a venous EDTA tube supplies ample well mixed whole blood without the interstitial fluid dilution and hemolysis risk that come with a skin puncture. Capillary A1c testing does exist on waived devices and is used where venous access is difficult, so it is not forbidden. Microtubes with EDTA are readily available, and pain is a poor basis for the choice.

A lancet has been used for a fingerstick and the collection is complete. How is it discarded?

• a.Rinse it under running water and place it in the regular waste after the blood is removed
• b.Retract the blade, then set it on the tray until the whole round of patients is finished
• c.Place it in a red biohazard bag along with the used gauze and the wrappers
• d.Drop it into a sharps container at the point of use, without recapping or resheathing✓

Any device that has punctured skin goes straight into a puncture resistant sharps container at the place it was used, not into a bag, a tray or the ordinary trash. A biohazard bag holds soft regulated waste and offers no protection against a blade. Rinsing a contaminated sharp creates a splash hazard, and carrying used sharps around is how injuries to housekeeping staff happen.

Which single factor has the greatest influence on whether a blood culture will detect an organism that is present?

• a.The brand of bottle used, because each manufacturer's broth recovers a different set of organisms
• b.The volume of blood placed in each bottle before it is sent for incubation✓
• c.Whether the aerobic bottle or the anaerobic bottle is inoculated first from the collection set
• d.The gauge of the needle, since a wider bore protects the organisms from mechanical damage

Bacteria are present in very small numbers in adult bloodstream infections, so recovery rises with the amount of blood cultured, and an underfilled bottle is a leading cause of a false negative that leaves a septic patient on the wrong antibiotic. Adult bottles are typically filled with eight to ten millilitres each; follow the manufacturer's stated volume. Order of inoculation and needle gauge matter far less.CLSI M47

How should the rubber septum on the top of a blood culture bottle be prepared before the blood is added?

• a.Scrub it with povidone iodine and leave the iodine in place so it keeps working during transport
• b.Wipe it with seventy percent alcohol and let it dry before the needle goes through✓
• c.Remove the plastic flip cap and add the blood at once, since the septum beneath is already sterile
• d.Flame the septum briefly with a lighter to sterilise the surface before the needle passes through

The flip cap keeps the septum clean but does not sterilise it, so the exposed rubber is disinfected with alcohol and allowed to dry before the needle goes through. Iodine is used on the patient's skin rather than on the bottle, because iodine residue can degrade the septum and is unnecessary there. Flaming a bottle top is not an accepted practice in any modern collection standard.CLSI M47

A blood culture set is being collected with a winged blood collection set. Which bottle is inoculated first and why?

• a.The anaerobic bottle, so that no oxygen at all can reach the organisms that need an oxygen-free space
• b.Whichever bottle is nearest, because the two bottles contain exactly the same broth and additive
• c.The anaerobic bottle, because it is the one that has to be filled to the line for the culture to count
• d.The aerobic bottle, because the air in the tubing enters the first bottle attached✓

A winged set holds a small volume of air in its tubing, and that air goes into whichever bottle is attached first. Sending it into the aerobic bottle is harmless, while sending it into the anaerobic bottle works against the very condition that bottle exists to create. When a syringe is used the situation differs, so follow the manufacturer's and the facility's stated sequence.CLSI M47

Why are two blood culture sets usually drawn from two separate venipuncture sites?

• a.Because an organism growing in only one set points toward skin contamination rather than infection✓
• b.Because a single venipuncture site cannot yield enough blood to fill two bottles in an adult patient
• c.Because the laboratory needs a duplicate specimen in case the first one is dropped or mislabelled
• d.Because facility policy requires that every microbiology specimen be collected twice for accuracy

Two sets from two sites let the laboratory interpret what grows. A skin organism such as a coagulase-negative staphylococcus appearing in one set of four bottles usually reflects contamination introduced at that puncture, while the same organism in both sets suggests a real bloodstream infection. Volume, breakage and blanket duplication policies are not the reason.CLSI M47

When does the timing clock start for the specimens of a two-hour glucose tolerance test?

• a.When the fasting specimen is collected, since that is the first sample in the whole series
• b.When the patient arrives at the laboratory and is registered for the appointment that morning
• c.When the patient swallows the last of the glucose solution she was given✓
• d.When the patient begins to drink, because the first mouthful is already being absorbed

The timed specimens are counted from the moment the patient swallows the last of the glucose load, which should be consumed within about five minutes. Starting the clock at the fasting draw or at registration shifts every subsequent specimen, and a glucose reported at the wrong interval can create or hide a diagnosis of diabetes. Exact collection times are documented on each tube.

During a glucose tolerance test the patient asks whether she may step outside for a cigarette between draws. What should the phlebotomist say?

• a.No, smoking is not permitted during the test and she should stay in the area✓
• b.Yes, provided she returns before the next timed specimen is scheduled to be collected
• c.Yes, because nicotine has no measurable effect on any blood glucose measurement at all
• d.Yes, but only if she agrees to have the remaining specimens collected by capillary puncture

Smoking stimulates the release of glucose from stores and can raise the measured value, so it is prohibted for the duration along with eating, drinking anything other than water and chewing gum. The patient also stays where staff can watch for hypoglycemia or fainting. Nicotine is not inert, and switching to capillary collection would change the specimen type mid-test.

A provider orders a trough level for an antibiotic. When is the specimen collected?

• a.Thirty minutes after the dose finishes infusing, when the drug is most evenly distributed
• b.At any convenient point in the dosing interval, as long as the exact time drawn is recorded
• c.Immediately before the next scheduled dose is due to be given to the patient✓
• d.Exactly halfway between two doses, which is the average concentration over the interval

A trough is the lowest concentration in the dosing interval and is measured just before the next dose, which is what tells the prescriber whether the drug stays above the level needed to work. A peak is drawn after the dose at a time that depends on the drug and route. Drawing at a random or midpoint time produces a number that cannot be interpreted, and the exact draw time is always recorded.

Which piece of information must be documented with a therapeutic drug monitoring specimen for the result to be interpretable?

• a.The patient's weight and height, so the laboratory can calculate the expected concentration
• b.The exact time the specimen was drawn and the time of the last dose✓
• c.The route by which the patient prefers to receive the medication in future dosing
• d.The name of the phlebotomist who collected it, which is what makes the result reportable

A drug level means nothing without its position in the dosing interval, so both the collection time and the time the last dose was given are recorded. Without them a prescriber cannot tell a safe trough from a toxic peak. The collector's identity is required on any specimen for traceability but it is not what makes a drug level interpretable, and the laboratory does not calculate expected concentrations from body size.

A blood alcohol level is ordered as part of a legal proceeding. How is the skin prepared?

• a.With seventy percent isopropyl alcohol, which is the routine antiseptic for every venipuncture
• b.With an alcohol-based chlorhexidine scrub, the same preparation used for blood cultures
• c.With no antiseptic at all, because any preparation would invalidate a legal specimen
• d.With a non-alcohol antiseptic such as aqueous benzalkonium chloride or soap and water✓

Alcohol-containing preparations, including alcohol-based chlorhexidine, can be challenged as a source of the measured alcohol, so a non-alcohol antiseptic is used and the choice is documented. The site is still disinfected; leaving it unprepared would create an infection risk and would not help the case. The tube is filled completely and handled under chain of custody.

What does a chain of custody record establish for a forensic specimen?

• a.That the laboratory used an instrument that was calibrated on the morning the specimen was analysed
• b.That the patient consented in writing to the test and understood what it would be used for
• c.That the specimen was collected within the window of time the court order specified
• d.Who had the specimen at every moment from collection to analysis, with signatures and times✓

The chain of custody is an unbroken written record of possession. Each person who handles the sealed specimen signs and dates it, so it can be shown in court that the sample tested is the sample taken and that no one had an unrecorded opportunity to alter it. Consent, calibration and collection timing are all real requirements but each is documented somewhere else.

A patient with hereditary hemochromatosis is scheduled for therapeutic phlebotomy. What is the purpose of the procedure?

• a.To remove a measured volume of blood in order to reduce the patient's iron burden✓
• b.To collect a diagnostic specimen large enough for the full panel of iron studies to be repeated
• c.To obtain a unit of blood that will be transfused into another patient on the same day
• d.To replace the patient's plasma with donor plasma while returning the red cells to the patient

Therapeutic phlebotomy removes red cells, and with them iron, on a physician's order, typically about five hundred millilitres at a session, and it is also used in polycythemia vera to reduce red cell mass. It is treatment, not diagnosis. The blood is generally discarded rather than transfused, and exchanging plasma is a different procedure performed with an apheresis machine.

Which needle gauge is typically used to collect a unit of blood from a volunteer donor?

• a.A 23 gauge, the same as the winged set used for a difficult outpatient venipuncture
• b.A 21 gauge, matching the routine choice for a diagnostic evacuated tube collection
• c.A 16 to 18 gauge, because the wide lumen protects the red cells in a large collection✓
• d.A 25 gauge, since a slower fill gives the anticoagulant in the bag more time to mix in

Donor collection uses a large bore needle so that roughly a pint of blood flows quickly through a wide lumen without shearing the red cells, which preserves the unit for transfusion. A diagnostic gauge would take far too long and would hemolyze the product. A 25 gauge is not used for whole blood collection at all because of the damage it causes.

Which specimen must be kept at body temperature from collection until it reaches the laboratory?

• a.A plasma ammonia, which is transported in an ice slurry to slow the breakdown of the analyte
• b.A serum bilirubin, which is wrapped in foil so that light cannot degrade the pigment in transit
• c.A prothrombin time, which is transported at ordinary room temperature within the stated window
• d.A cold agglutinin titre, which must be kept at 37 degrees Celsius so the antibody stays free✓

Cold agglutinins bind to red cells as the specimen cools, so a sample allowed to reach room temperature loses antibody from the serum and the titre is reported falsely low. The tube is prewarmed and carried in a heat block. Ammonia is chilled, bilirubin is protected from light and a coagulation specimen travels at room temperature, so each of the others names a real requirement for the wrong reason.

How should a specimen that requires chilling be transported to the laboratory?

• a.Buried in a container of solid ice cubes, which hold their temperature longer than anything else
• b.In a household freezer compartment until a courier is available to take it across to the laboratory
• c.In a refrigerator at four degrees, after the tube has first been centrifuged on the collection floor
• d.In a slurry of crushed ice and water, so the whole tube cools evenly without freezing✓

A mixture of ice and water surrounds the tube completely and holds it near zero degrees without letting any part of the specimen freeze. Solid cubes touch the glass at points, so parts of the sample freeze and hemolyze while other parts stay warm. Freezing a whole blood specimen ruptures the cells, and a chilled specimen is not the same as a centrifuged and refrigerated one.

A patient has a central venous catheter and a stat potassium is ordered. Who may draw the specimen from that line?

• a.Only a nurse or other clinician specifically trained and authorised to access central lines✓
• b.The phlebotomist, provided the line is flushed with saline before and after the specimen is drawn
• c.The phlebotomist, as long as a discard volume of at least five millilitres is taken and thrown away
• d.Anyone in the department, because a central line needs no venipuncture skill

Accessing a central line carries risks of infection, air embolism and catheter damage, so it is restricted to staff trained and credentialled for it, and phlebotomists are usually not among them. Flushing and discarding are part of the technique for those who are authorised, not a substitute for the authorisation. A specimen drawn from a line without the discard is also diluted by whatever was infusing.

Before an arterial puncture at the radial site, what does the modified Allen test determine?

• a.Whether the radial artery is large enough to accept the gauge of needle that has been selected
• b.Whether the patient's blood pressure is high enough for the syringe to fill without aspiration
• c.Whether the ulnar artery can supply the hand if the radial artery becomes blocked✓
• d.Whether the patient has enough clotting factor to stop bleeding after the needle is withdrawn

Both hand arteries are compressed until the hand blanches, then the ulnar is released. Colour returning within a few seconds shows collateral circulation, so the hand would survive if the radial artery thrombosed after the puncture. It says nothing about vessel size, blood pressure or coagulation, and arterial puncture itself is performed only by personnel trained and authorised for it.

An arterial blood gas syringe has a small air bubble in it after collection. What must be done?

• a.Expel the bubble at once and cap the syringe, because air alters the measured oxygen✓
• b.Leave the bubble in place, since it will dissolve into the plasma long before analysis begins
• c.Draw the plunger back to enlarge the bubble so it can be seen and reported to the laboratory
• d.Shake the syringe vigorously so the bubble is dispersed evenly

Room air holds much more oxygen and much less carbon dioxide than blood, so a retained bubble raises the measured oxygen and lowers the carbon dioxide, which can make a hypoxic patient look adequately oxygenated. The bubble is expelled immediately, the syringe is capped, the specimen is mixed gently and it goes straight to the laboratory. Shaking hemolyzes the sample.

How long should pressure be held over an arterial puncture site compared with a venous one?

• a.The same length of time, because the puncture wound in the skin is identical in both cases
• b.Less time, because arterial pressure pushes the vessel walls together and seals the site faster
• c.Longer, three to five minutes, and longer still if the patient is anticoagulated✓
• d.No pressure is needed at all if a pressure dressing is applied directly over the site

An artery carries blood under far higher pressure than a vein, so it bleeds longer and can form a large deep hematoma if released early. Continuous firm pressure for three to five minutes is the usual minimum, extended for patients on anticoagulants or with a bleeding disorder, and the site is then rechecked. A dressing alone does not substitute for held pressure.

A serum cortisol is ordered for eight in the morning and the patient arrives at four in the afternoon instead. What should the phlebotomist do?

• a.Draw the specimen now and label it as the eight in the morning collection to keep the order intact
• b.Draw it now without comment, because cortisol is stable and the time of day is irrelevant
• c.Refuse the draw and send the patient home to return at eight in the morning another day
• d.Draw it, record the actual collection time, and notify the provider that the timing has changed✓

Cortisol follows a daily rhythm and is typically highest in the early morning and much lower late in the day, so an afternoon specimen cannot be compared with a morning reference interval. The phlebotomist records the true time and lets the provider decide whether to use it or rebook. Labelling a specimen with a time it was not drawn is falsification of a record.

A patient is scheduled for autologous blood donation. What does that mean?

• a.Blood is collected from a relative whose type has been matched
• b.Blood is collected and separated so that only the plasma is returned to the patient later on
• c.Blood is collected from several donors and pooled into one unit for a single planned operation
• d.The patient's own blood is collected in advance and stored for their own planned surgery✓

In an autologous donation the donor and the recipient are the same person, which removes the risk of a transfusion reaction and of transmitted infection. Blood taken from a named relative or friend is a directed donation, a different arrangement. Pooling units from several donors and returning a separated component are both different procedures with different indications.

Which requirement applies specifically to a blood bank specimen for a type and crossmatch?

• a.The tube is labelled at the bedside with the identifiers plus who drew it and when✓
• b.The tube must be the last one filled in the draw so that no additive can be carried into it
• c.The specimen must be collected by two phlebotomists together
• d.The tube must be transported to the laboratory in an ice slurry to preserve the red cell antigens

Almost every fatal transfusion reaction begins with a specimen labelled for the wrong patient, so blood bank rules add the collector's identity and the date and time to the usual identifiers, and the label goes on at the patient's side before the phlebotomist leaves. Two collectors are not required, the specimen travels at room temperature, and the blood bank tube is not drawn last.

Which specimen requires protection from light between collection and analysis?

• a.A potassium level, because light drives potassium out of the cells
• b.A blood culture set, because light kills the more fragile organisms before they can grow
• c.A serum bilirubin, because light breaks the pigment down and the result reads low✓
• d.A prothrombin time, because light activates the clotting factors and shortens the result

Bilirubin is photosensitive, and a specimen left in daylight or under a phototherapy lamp loses measurable pigment within an hour, which can hide a rising bilirubin in a jaundiced newborn. Carotene, vitamin A, vitamin B6 and folate are handled the same way. Light does not move potassium, kill culture organisms or activate coagulation factors.

A two-hour postprandial glucose is ordered. What instruction does the patient need?

• a.Fast for twelve hours and arrive with nothing to eat or drink since the previous evening
• b.Eat the meal the provider specified, then return exactly two hours after starting it✓
• c.Eat whatever the patient likes at any time, since the two-hour interval is the only variable
• d.Drink the standard glucose solution and wait for two hours

The two-hour postprandial specimen measures how the body handles a defined meal, so the patient eats the prescribed meal and the timing runs from the start of eating. Continuing to fast defeats the purpose, an unspecified meal makes the result impossible to compare, and drinking a measured glucose load is a tolerance test, which is a different order.

A blood culture set drawn from an arm with a running intravenous line grows a skin organism in one bottle only. What is the most likely explanation?

• a.Contamination introduced during collection rather than a true bloodstream infection✓
• b.A genuine bloodstream infection that the second set simply failed to detect on that occasion
• c.Contamination of the culture medium during manufacture, which requires a recall of the lot
• d.Cross contamination in the analyser, which incubates all of the bottles in one shared chamber

A skin organism in one bottle of one set, with the other bottles negative, is the classic pattern of contamination introduced at the puncture, usually from inadequate skin antisepsis or from touching the prepared site. Manufacturing contamination and analyser cross contamination are rare and would show a different pattern, and a true infection generally seeds more than one bottle.

Why is a pre-employment drug screen collected under chain of custody rather than as a routine specimen?

• a.Because the analysis is performed on urine, and urine always requires additional documentation
• b.Because the laboratory charges a higher fee for any test that an employer rather than a patient orders
• c.Because the specimen has to be frozen and logged for temperature
• d.Because the result may cost someone a job and must be defensible if it is challenged✓

A drug screen carries a consequence outside medical care, so the specimen is sealed, initialled and tracked through every transfer, and the donor confirms the seal. That record is what allows the result to withstand a legal challenge. Specimen type, cost and storage temperature do not determine whether chain of custody applies; the use the result will be put to does.

A box of lavender tubes in the drawer passed its expiration date two weeks ago. What is the concern?

• a.The plastic of the tube itself begins to break down and leaches into the blood specimen
• b.The label adhesive fails, so the tube can no longer be labelled
• c.The vacuum and the additive may no longer perform as the manufacturer guarantees✓
• d.Nothing, provided the box was stored in a cool dry place away from sunlight

An expiration date certifies the draw volume and the additive activity, so an expired tube can underfill or fail to anticoagulate properly, and a short-filled EDTA tube gives a falsely low hematocrit while a poorly anticoagulated one clots. Expired stock is removed from service rather than used carefully. Storage conditions matter but do not extend the date, and the plastic does not degrade into the sample.

What is the function of the rubber sleeve that covers the back end of a multisample needle?

• a.It cushions the tube stopper so the glass cannot crack when the tube is pushed onto the needle
• b.It closes over the needle between tubes so blood does not leak while tubes are changed✓
• c.It holds the additive that will be released into the first tube attached to the holder
• d.It keeps the needle sterile while it is inside the patient's vein during the collection

The sleeve is a one-way valve. Tube pressure pushes it back so blood enters, and it springs closed the moment the tube is removed, which is what allows several tubes to be filled through one venipuncture without blood escaping into the holder. It carries no additive, provides no cushioning and plays no part in sterility once the needle is in the vein.

A blood smear is made from an EDTA tube using the wedge technique. Which detail matters most for a usable slide?

• a.The drop is placed at the centre of the slide so the film spreads evenly in both directions at once
• b.The spreader slide is held at roughly a thirty degree angle and pushed with one smooth motion✓
• c.The slide is warmed on a slide dryer before the drop of blood is placed on its surface
• d.The film is spread slowly enough that it covers the entire slide from end to end

A shallow, steady push at about thirty degrees produces a film with a feathered edge, which is the thin area where the cells lie in a single layer and can be identified and counted. A steeper angle makes the film short and thick, a slower push makes it too long, and covering the whole slide leaves no feathered edge at all. The drop goes near one end, not the centre.

A blood pressure cuff is used in place of a tourniquet on a patient with difficult veins. How should it be used?

• a.Inflate it above the patient's systolic pressure so the vein fills fully
• b.Inflate it to the patient's diastolic pressure and leave it there until every tube is filled
• c.Leave it deflated and rely on the width of the cuff alone to compress the superficial veins
• d.Inflate it below the diastolic pressure and release it within the same one minute limit✓

A cuff works like a tourniquet only if it obstructs venous return while arterial inflow continues, which means a pressure below diastolic. Inflating above systolic stops arterial flow altogether and the vein does not fill. The one minute limit still applies, because hemoconcentration develops just as it does under a rubber tourniquet, and a deflated cuff compresses nothing.

Which vein is generally the second choice for antecubital venipuncture when the median cubital cannot be used?

• a.The cephalic vein, which lies on the thumb side of the arm✓
• b.The basilic vein, because it is usually the most visible of the three
• c.The radial artery, provided the modified Allen test is normal
• d.Any vein on the inner wrist, where the vessels run straighter

The order of preference runs median cubital, then cephalic, then basilic. The cephalic lies laterally and can be harder to anchor because it tends to roll, but it is away from the median nerve and the brachial artery that make the basilic the last resort. An artery is never a substitute for a vein in routine collection, and the inner wrist is avoided entirely.

A phlebotomist must draw a patient who is on contact precautions in an isolation room. What happens to the collection tray?

• a.The whole tray is carried in and wiped down with disinfectant on the way back out of the room
• b.The tray is carried in but placed on the floor rather than on any surface in the room
• c.The tray stays outside; only the supplies needed for that draw are taken in✓
• d.The tray is carried in and left in the room until the patient is discharged from isolation

Anything taken into an isolation room is treated as contaminated, so the shared tray stays outside and the phlebotomist carries in only what the draw requires, plus a little margin. Wiping a tray that has sat on an isolation surface is less reliable than never exposing it, the floor is the most contaminated surface in any room, and leaving a shared tray behind removes it from service.

A waived point of care prothrombin time device is used in an anticoagulation clinic. What does the CLIA waived designation mean?

• a.The test may be performed without any quality control, documentation or operator training at all
• b.The result carries no clinical weight and always has to be confirmed by the central laboratory
• c.The test is simple enough to have a low risk of erroneous result, but rules still apply✓
• d.The facility does not need a CLIA certificate of any kind in order to perform the test

A waived test is one the manufacturer has shown to be simple and low risk when the instructions are followed, and the facility still needs a CLIA certificate of waiver, trained operators, manufacturer quality control and records. Waived results are used clinically. Skipping quality control, or believing that no certificate is needed, are the two errors that turn a waived test into a citation.

A requisition asks for a test the phlebotomist has never heard of and gives no tube type. What should be done first?

• a.Draw one tube of every colour available so that the laboratory is certain to have what it needs
• b.Check the laboratory's specimen requirements, and call the laboratory if it is still unclear✓
• c.Draw a lavender tube, since whole blood can be used for the widest range of tests
• d.Ask the patient which tube was used the last time this same test was ordered

Every laboratory publishes a specimen requirement list or online directory giving tube type, volume, handling and stability for each test, and a phone call resolves anything the directory does not. Drawing a full rainbow of tubes takes blood the patient does not need to give, guessing at a lavender wastes the draw when serum is required, and a patient is not a source of specimen requirements.

Why does prolonged tourniquet application raise the measured total protein and calcium?

• a.Because the pressure squeezes protein out of the muscle tissue and into the vein below the cuff
• b.Because the vein warms under the tourniquet and warm plasma carries more protein in solution
• c.Because the tourniquet stops arterial inflow, so the cells consume the remaining water
• d.Because water and small molecules leave the vessel while large molecules stay behind✓

Obstructed venous return raises pressure inside the vessel, and water and small solutes filter out into the tissue while proteins and anything bound to them, including much of the calcium, are held back. The remaining plasma is concentrated, so protein, calcium, cholesterol, iron and cell counts all read high. Releasing the tourniquet within a minute keeps the effect clinically negligible.

A phlebotomist draws blood into a syringe and then fills a citrate tube, a heparin tube and an EDTA tube. In what order should the tubes be filled?

• a.Citrate, then heparin, then EDTA, which is the same relative order as an evacuated tube draw✓
• b.EDTA first, because the cells begin to clot in the syringe and the count is the most fragile result
• c.Heparin first, then citrate, then EDTA, because heparin is the least affected by any delay
• d.Any order, since the blood is already mixed in the barrel and no carryover can occur

The blood in a syringe begins to clot from the moment it is drawn, so the coagulation tube is filled first and the transfer is completed quickly. The relative order of the tubes does not change with the collection method. Carryover is no longer the reason, but clot formation is, and it argues for the same sequence rather than a different one.

How long should an adhesive bandage stay on after a routine venipuncture on an adult?

• a.Until the patient's next appointment, so the site is protected from any knock in the meantime
• b.Around fifteen minutes, or longer if the patient bruises easily or takes an anticoagulant✓
• c.Ten seconds, just long enough for the phlebotomist to confirm the bleeding has already stopped
• d.Overnight, because a venipuncture wound needs a full night to close completely

A quarter of an hour is the usual advice, with longer for a patient who bleeds or bruises easily, and the patient is told to keep the arm straight and avoid heavy lifting with it for a while. Removing it within seconds risks the site reopening, and leaving an adhesive on for a day irritates the skin without adding any protection.

A patient in a wheelchair needs an outpatient blood draw. What is the safest arrangement?

• a.Ask the patient to stand and lean against the drawing chair for the few seconds the draw takes
• b.Draw the patient in the wheelchair without touching the brakes, so it can be moved in an emergency
• c.Lock the wheelchair brakes and support the arm, or transfer the patient with help if needed✓
• d.Lift the patient into the phlebotomy chair without assistance so that no time is lost

The chair is immobilised and the arm is supported on a firm surface so neither the patient nor the phlebotomist has to hold a position that could slip. Where the facility requires a transfer it is done with help and with the correct equipment. Asking a wheelchair user to stand, leaving the brakes off and lifting a patient alone all invite a fall or a back injury.

Which practice best prevents a wrong-patient specimen in a busy outpatient drawing area?

• a.Pre-labelling the tubes for the next three patients so that no label can be mixed up later
• b.Labelling each tube at the chair after the draw and comparing the label with the patient✓
• c.Writing the patient's initials on the tube and adding the full label at the end of the shift
• d.Keeping each patient's tubes in a separate rack and labelling the whole rack at once

Labels are applied one patient at a time, at the point of collection, and read back against the requisition and the patient before the phlebotomist moves on. Pre-labelling puts a correct label on the wrong blood the first time a patient is called out of order, and any scheme that defers labelling relies on memory, which is what fails on a busy morning.

A phlebotomist notices that the sharps container in the drawing room is filled past the marked line. What should be done?

• a.Press the contents down carefully with a gloved hand so that more room becomes available
• b.Continue using it until the end of the shift and raise it with the lead afterwards
• c.Empty the container into the biohazard waste bin and put the empty container back in place
• d.Close and replace it, and do not use it again once it has reached the fill line✓

Overfilling is how sharps protrude from the opening and injure the next person to use the container or the staff who transport it, so a container is sealed and exchanged when it reaches the manufacturer's line, usually about three quarters full. Pressing contents down puts a hand directly over exposed needles, and a sharps container is never emptied on site.

Which finding on a filled tube tells the phlebotomist that the draw volume was correct?

• a.The blood reaches the very top of the tube and touches the stopper
• b.The tube feels heavy enough that the additive is certain to be fully dissolved in the blood
• c.The blood stops at the manufacturer's fill indicator and the vacuum has exhausted itself✓
• d.The blood covers about half the tube, leaving room for the additive to mix during inversion

An evacuated tube draws exactly the volume its vacuum was calibrated for, so the tube stops filling on its own at the indicated line and that is the signal to remove it. No tube is designed to fill to the stopper, and a half-filled additive tube has the wrong blood to additive ratio, which prolongs a coagulation time or shrinks red cells depending on the additive. Weight is not a usable check.

An inpatient's requisition is marked as a timed draw for six in the morning, and the phlebotomist arrives at seven fifteen. What should be recorded?

• a.The actual time the specimen was drawn, with a note explaining the delay✓
• b.The ordered time of six in the morning, because that is the time the provider requested
• c.No time at all, since the laboratory computer stamps the specimen when it is received
• d.An average of the ordered time and the actual time, which is the fairest representation

The collection time recorded is the time the blood was actually drawn, and the reason for a missed window is documented so the provider can judge whether the result still answers the question. Recording the ordered time is a false entry that can lead to a drug dose or an insulin adjustment based on a level from the wrong point in the cycle. A receipt stamp is not a collection time.

What should a phlebotomist do with a tube that was accidentally drawn out of the standard order?

• a.Nothing, as long as all of the tubes were inverted immediately after they were filled
• b.Report it, and redraw the affected tube if the laboratory says the test could be compromised✓
• c.Discard every tube from the draw and start again with a fresh venipuncture on the other arm
• d.Note it on the requisition and send the tubes, since the laboratory expects occasional variation

The person who knows the sequence was wrong is the only one who can say so, and the laboratory then decides which results are at risk, because that depends on which additive reached which tube. Silence lets a falsely high potassium or a prolonged clotting time be reported as real. An automatic full redraw takes blood the patient may not need to give again.

A phlebotomist is about to draw a patient whose requisition and wristband show the same name but different dates of birth. What should happen?

• a.Draw the specimen and label it with the date of birth that appears on the wristband
• b.Draw the specimen and label it with the date of birth printed on the requisition form
• c.Stop and resolve the discrepancy with the nurse before any blood is collected✓
• d.Ask the patient which date is correct and change the requisition to match the answer

Two identifiers that do not agree mean identity has not been established, and no specimen is collected until the record is corrected by the staff responsible for it. Choosing one source over the other guesses at which document is wrong, and altering a requisition is outside the phlebotomist's role even when the patient's answer sounds convincing. Two patients can share a name.

Which action should a phlebotomist take immediately after entering a patient's room and before touching any equipment?

• a.Put on gloves straight from the box at the door so the hands are covered from the outset
• b.Set the collection tray down on the bedside table so both hands are free to work
• c.Open the tube packaging so the tubes are ready the moment the vein has been located
• d.Perform hand hygiene, then introduce yourself and confirm the patient's identity✓

Hand hygiene comes before patient contact, followed by introduction and identification, and gloves go on after the hands are clean and immediately before the puncture. Gloves put on over unwashed hands transfer whatever was on them, a tray placed on a bedside table contaminates a patient surface, and opening supplies before the site is chosen wastes them if plans change.

A patient asks the phlebotomist what the ordered tests are for. What is the appropriate response?

• a.Explain what each test measures and what an abnormal result would probably mean for the patient
• b.Say which tests were ordered, and refer questions about their purpose to the provider✓
• c.Decline to say anything at all about the requisition, since test names are protected information
• d.Give a general reassurance that the tests are routine and that the results are certain to be normal

Naming the tests is within a phlebotomist's role, while interpreting them or explaining why they were ordered belongs to the person who ordered them. Refusing to say anything is unnecessary secrecy toward the patient whose own information it is, and promising a normal result is a prediction the phlebotomist cannot make and the patient may remember.

Which set of details must a phlebotomist document after a failed venipuncture attempt on an inpatient?

• a.The attempt, the site used and who was notified or asked to complete the collection✓
• b.The name of the vein only, since no specimen was obtained and there is nothing else to report
• c.The patient's stated reason for having difficult veins and their history of previous draws
• d.Nothing, because documentation is required only when a specimen actually reaches the laboratory

An unsuccessful attempt still happened to the patient, so the record shows that it was made, where, and how the order was resolved, whether by a colleague, by the nurse or by contacting the provider. That record prevents a fourth and fifth puncture by someone who does not know what has already been tried, and it is exactly the note that is missing when a complaint is reviewed.