NHA Phlebotomy Technician (CPT) — All Questions

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.