NHA Phlebotomy Technician (CPT) — All Questions

Which set of elements must appear on a blood specimen label?

• a.Patient full name, a second unique identifier, date and time of collection, and the collector's identification✓
• b.Patient room number and diagnosis
• c.Ordering provider and insurance number
• d.Patient last name and the test name only

A compliant label carries the patient's full name plus a second unique identifier such as the medical record number or date of birth, the date and time of collection and the identity of the person who collected it. Room numbers and diagnoses change and are not unique identifiers. Test names and billing information belong on the requisition, not in place of patient identification.CLIA

When and where should blood tubes be labeled?

• a.At the patient's side immediately after collection, before leaving the patient✓
• b.At the nurses' station after all patients on the floor are collected
• c.Before the draw, so the tubes are ready
• d.In the laboratory after delivery, using the requisition

Tubes are labeled at the bedside immediately after collection and before leaving the patient, which is the only point at which identity can still be verified against the patient. Pre-labeling risks putting the wrong patient's blood in an already labeled tube. Labeling later in the laboratory or at a workstation makes mislabeling likely and is a leading cause of transfusion and diagnostic errors.CLIA

Which specimen must be transported chilled in an ice slurry?

• a.Bilirubin
• b.Cold agglutinins
• c.Complete blood count
• d.Ammonia✓

Ammonia rises rapidly at room temperature as cells continue to metabolize, so the tube is chilled in an ice and water slurry and delivered immediately. Bilirubin is protected from light rather than chilled, and cold agglutinins must be kept at body temperature because cooling causes the antibody to bind red cells. A CBC is transported at room temperature.CLSI GP44

A neonatal bilirubin is collected. How must the specimen be handled during transport?

• a.Protected from light, for example with an amber tube or foil wrap✓
• b.Kept in an ice slurry for at least 30 minutes
• c.Left uncovered at room temperature to allow clotting
• d.Frozen immediately at minus 20 degrees Celsius

Bilirubin is photosensitive and degrades within minutes of light exposure, so an amber microtube or foil wrapping is used. Vitamin B12, folate, carotene and vitamin A require the same protection. Freezing whole blood hemolyzes it, chilling is not the required protection here, and leaving the tube exposed causes falsely low results.CLSI GP44

A cryofibrinogen test is ordered. What handling is required?

• a.Transport on ice
• b.Refrigerate at 4 degrees Celsius for one hour before centrifuging
• c.Keep the specimen at 37 degrees Celsius until processed✓
• d.Freeze the whole blood immediately

Cryofibrinogen, cryoglobulins and cold agglutinins precipitate or bind when cooled, so the specimen is kept warm at body temperature from collection through processing, often using a prewarmed tube and a 37 degree carrier. Icing or refrigerating causes the target protein to drop out of solution and gives falsely low results. Freezing whole blood destroys the cells entirely.CLSI GP44

Within what time should serum or plasma be separated from cells for routine chemistry testing?

• a.Within 8 hours of collection
• b.Only after the specimen has been refrigerated overnight
• c.Within 2 hours of collection✓
• d.Within 24 hours if refrigerated

Serum or plasma should be physically separated from the cells within two hours of collection, because continued cellular metabolism lowers glucose and raises potassium, LDH and phosphorus. Holding the tube for 8 or 24 hours before separation produces clinically misleading results. Refrigerating an unseparated tube actually accelerates potassium leakage from red cells.CLSI GP44

Which collection practice is most likely to hemolyze a specimen?

• a.Letting the alcohol dry fully before puncture
• b.Forcing blood from a syringe through the needle into an evacuated tube✓
• c.Using a 21 gauge needle on a good antecubital vein
• d.Inverting an EDTA tube gently eight times

Pushing blood through a narrow needle under pressure shears red cells and is a classic cause of hemolysis, which is why a transfer device is used instead. Gentle inversion, an appropriately sized needle and fully dried alcohol all reduce hemolysis. Hemolysis falsely raises potassium, LDH, AST and magnesium and often forces a redraw.CLSI GP41

A chemistry specimen arrives visibly hemolyzed. Which result is most likely to be falsely elevated?

• a.Chloride
• b.Sodium
• c.Albumin
• d.Potassium✓

Potassium is far more concentrated inside red cells than in plasma, so cell rupture releases it and drives the measured value up sharply. LDH, AST and magnesium rise for the same reason. Sodium and chloride are higher outside the cells, and albumin is a plasma protein unaffected by red cell lysis.CLSI GP44

A lavender tube submitted for a CBC contains visible small clots. What should happen?

• a.Reject the specimen and recollect, because clotting invalidates cell counts✓
• b.Filter the specimen and then run it
• c.Run the CBC and add a comment about clots
• d.Add extra EDTA and mix again

Clots consume platelets and trap white and red cells, so counts are falsely low and the specimen must be rejected and recollected with prompt, adequate mixing. Commenting on a clotted CBC still reports unreliable numbers. Filtering removes cells that should be counted, and adding anticoagulant after the fact cannot reverse clot formation.CLIA

An unlabeled tube arrives in the laboratory with a completed requisition attached. What is the correct action?

• a.Ask the phlebotomist who drew it to label it now
• b.Label it from the requisition and process it
• c.Process it and hold the result until labeling is confirmed
• d.Reject the specimen and request recollection✓

An unlabeled specimen cannot be positively linked to a patient, so it is rejected and recollected, and the event is documented. Labeling after the fact from a requisition or from memory is exactly how patients receive another patient's results. Only irreplaceable specimens such as cerebrospinal fluid have a special resolution process, and whole blood is not in that category.CLIA

An EDTA specimen is collected for a CBC with a manual differential. What time limit applies to making the blood smear?

• a.Timing does not matter because EDTA preserves morphology indefinitely
• b.Smears must be made after refrigerating the tube overnight
• c.Smears may be made up to 24 hours later at room temperature
• d.Smears should be prepared within about one hour of collection✓

EDTA preserves cells for automated counting for roughly 24 hours, but white cell and platelet morphology begins to distort within a few hours, so smears are made within about one hour. Waiting a day produces artifacts that mimic disease. Refrigeration does not restore morphology, and no anticoagulant preserves cell shape indefinitely.CLSI GP44

A gel serum separator tube has already been centrifuged and the serum is above the gel. A repeat test is requested. What should be done?

• a.Test from the serum already above the gel, or aliquot it into a labeled tube✓
• b.Freeze the whole tube and thaw it before testing
• c.Shake the tube to remix the serum with the cells
• d.Recentrifuge the original tube to obtain more serum

Once the gel barrier has formed, the serum above it is stable and can be tested or aliquotted into a properly labeled tube. Recentrifuging a gel tube can force cellular contents into the serum and falsely raise potassium. Remixing serum with cells or freezing the tube with cells still present destroys specimen integrity.CLSI GP44

Which specimen requirement applies to an erythrocyte sedimentation rate?

• a.It should be tested within about four hours at room temperature✓
• b.It requires a serum separator tube
• c.It must be protected from light
• d.It must be frozen if not tested within one hour

An ESR is performed on a well-mixed EDTA specimen and should be set up within about four hours at room temperature, because red cells lose their normal shape over time and settle differently. Freezing destroys the cells, and light does not affect sedimentation. A serum tube is unusable because the test requires anticoagulated whole blood.CLSI GP44

Unless a test specifies otherwise, at what temperature are routine blood specimens transported?

• a.At ambient room temperature, roughly 15 to 30 degrees Celsius✓
• b.Frozen at minus 20 degrees Celsius
• c.Refrigerated at 2 to 8 degrees Celsius
• d.Warmed to 37 degrees Celsius

Most routine specimens travel at ambient room temperature unless the test specifically calls for chilling, freezing or warming. Routine refrigeration of unseparated blood raises potassium as it leaks from red cells. Freezing whole blood causes hemolysis, and warming is reserved for cold-sensitive analytes such as cryoglobulins.CLSI GP44

A tube is submitted with far less blood than the test requires. How is this documented as a rejection reason?

• a.Chain of custody break
• b.Quantity not sufficient✓
• c.Delayed transport
• d.Improper additive

An underfilled specimen that cannot support the ordered testing is reported as quantity not sufficient, and the laboratory requests recollection. A chain of custody break involves lost documentation of handling, an improper additive means the wrong tube was used, and delayed transport refers to exceeding time limits. Each of these is a distinct rejection category with a different corrective action.CLIA

A routine urinalysis cannot be tested for 90 minutes. What is the correct interim handling?

• a.Refrigerate the specimen or use a chemical preservative tube✓
• b.Add a small amount of bleach to prevent bacterial growth
• c.Freeze the specimen
• d.Leave it at room temperature and test when convenient

Urine should be tested within about two hours or refrigerated, because bacteria multiply and cells and casts break down at room temperature. A preservative transport tube is an accepted alternative. Freezing destroys formed elements, and adding a disinfectant contaminates the specimen and invalidates chemical testing.CLSI GP44

Serum is transferred into a secondary aliquot tube for send-out testing. What must be done?

• a.Combine aliquots from the same patient collected on different days
• b.Leave it unlabeled because the parent tube is labeled
• c.Label the aliquot with the same patient identifiers as the original tube✓
• d.Write only the accession number on the cap

Every aliquot is an independent specimen and must carry the same patient identifiers as the parent tube so identity is never lost. Relying on the parent tube or writing an identifier only on a removable cap breaks the chain of identification. Pooling specimens collected at different times mixes results from different clinical moments and is never acceptable.CLIA

A phlebotomist notices the expiration date on a box of lavender tubes passed last month. What is the concern?

• a.Vacuum and additive reactivity decline, so fill volume and results become unreliable✓
• b.Nothing, since expiration applies only to reagents
• c.The tube color will fade and cause misidentification
• d.The stopper will not fit the holder correctly

Evacuated tubes lose vacuum and additive effectiveness over time, so an expired tube may underfill or fail to anticoagulate properly, producing unreliable results. Expired tubes are removed from stock and not used. Color coding and stopper fit are not the reason for the date, and expiration dating applies to collection devices as well as reagents.CLIA

Why must additive tubes be mixed by gentle inversion rather than shaking?

• a.Shaking increases the vacuum inside the tube
• b.Gentle inversion is required only for serum tubes
• c.Shaking causes mechanical hemolysis and foaming that invalidate many tests✓
• d.Shaking dissolves the stopper lubricant into the specimen

Vigorous shaking shears red cells and creates foam, producing hemolysis that falsely raises potassium, LDH and AST and can prevent testing altogether. Gentle inversion distributes the additive without damaging cells and is required for every additive tube, not just serum tubes. Shaking has no effect on stopper lubricant or on the residual vacuum.CLSI GP41

A serum tube is centrifuged five minutes after collection and fibrin strands appear in the serum. What went wrong?

• a.The specimen was spun before the clot had fully formed✓
• b.The serum was exposed to light
• c.The tube contained too much clot activator
• d.The tube was centrifuged at too low a speed

A plain or gel serum tube needs roughly 30 minutes at room temperature to clot completely before centrifugation, and spinning early leaves fibrin that clogs analyzers and skews results. Speed affects separation quality but does not create fibrin. Clot activator quantity is fixed by the manufacturer, and light exposure affects photosensitive analytes rather than clot formation.CLSI GP44

What must be true before a serum tube with a clot activator is centrifuged?

• a.The tube must be chilled, so the clot contracts and separates cleanly from the serum
• b.The tube must be uncapped, so pressure does not build during the spin
• c.The tube must have clotted fully, usually about thirty minutes at room temperature✓
• d.The tube must be spun within five minutes of collection to prevent glycolysis

Spinning a specimen that has not finished clotting leaves fibrin in the serum, which blocks analyser probes and forces a redraw, and it can also produce a latent clot that forms after separation. Around thirty minutes upright at room temperature is typical for a clot activator tube. Stoppers stay on to contain aerosols, and chilling a serum tube slows rather than helps clotting.CLSI GP44

Which practice is required when loading a centrifuge with specimen tubes?

• a.Remove every stopper first so the serum can be poured off as soon as the rotor stops turning
• b.Balance the tubes opposite one another by size and by how full they are✓
• c.Place all of the tubes on one side of the rotor so they are easy to retrieve afterwards
• d.Run the centrifuge with the lid open so the operator can watch the tubes while they spin

An unbalanced rotor vibrates, which breaks tubes, hemolyses specimens and damages the instrument. Tubes are paired across the rotor by size and fill, with a water-filled balance tube if the count is odd. Stoppers stay on to contain the aerosol a spinning specimen creates, and the lid stays closed and latched throughout the run for the same reason.

Why do some laboratories forbid sending certain specimens through a pneumatic tube system?

• a.Because the tube system cannot carry a specimen fast enough to meet a stat turnaround time
• b.Because the carrier cannot be labelled, so specimens arrive without patient identification
• c.Because the acceleration and impacts can hemolyze cells and invalidate sensitive results✓
• d.Because a pneumatic system exposes specimens to light that degrades several analytes

Sudden acceleration, deceleration and the knock at each station shake the specimen enough to rupture red cells, which raises potassium and lactate dehydrogenase and can turn a normal potassium into a critical one. Laboratories therefore hand carry blood gases, some coagulation work and any specimen a physician flags. The system is fast, carriers are labelled and the tube is not transparent.

A tube of whole blood for a potassium is refrigerated overnight and separated the next morning. What happens to the result?

• a.Potassium reads falsely high because cold stops the pump that keeps it inside the red cells✓
• b.Potassium reads falsely low because the cold drives it from the plasma back into the cells
• c.Potassium is unaffected, because refrigeration is the recommended way to store whole blood
• d.Potassium cannot be measured at all once a specimen has been refrigerated for any length of time

Red cells hold potassium inside using an energy-dependent pump, and cooling whole blood slows that pump so potassium leaks into the plasma. A specimen left cold overnight can report a potassium high enough to trigger treatment for a patient whose true level is normal. Whole blood for chemistry is kept at room temperature and separated within the laboratory's stated limit.

Which specimen problem is a rejection reason that the phlebotomist can prevent at the bedside?

• a.A patient whose result is outside the reference interval for that analyte
• b.An analyser flag raised during the run in the laboratory
• c.A quantity of blood that is not sufficient for the ordered test✓
• d.A delay caused by the courier vehicle breaking down on the route

Short draws, clotted anticoagulant tubes, hemolysis, mislabelling and wrong tube type are all created at the point of collection and all cause rejection, and each of them is preventable by the person holding the needle. An abnormal result is a finding rather than a defect, an analyser flag arises during testing, and a courier breakdown is outside anyone's control at the bedside.

A specimen arrives in the laboratory with a label that has the correct name but no collection date or time. What normally happens?

• a.The specimen is discarded at once and the patient is called back for a fresh collection
• b.The laboratory writes in the time the specimen was received and processes it as usual
• c.The specimen is processed and the missing information is reported as a comment
• d.The collector is contacted to complete the label, and policy decides whether it may be used✓

Only the person who collected the specimen can supply a collection time, so the laboratory contacts that person rather than filling it in, and the facility's policy decides whether a completed label is acceptable or a recollection is required. Entering a receipt time as a collection time creates a false record, and discarding without asking wastes a specimen that may be recoverable.