CSLB General Building (B) — All Questions

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

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

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

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

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

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

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

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

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

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

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

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

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 must be protected from light
• c.It must be frozen if not tested within one hour
• d.It requires a serum separator tube

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

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.Leave it at room temperature and test when convenient
• c.Freeze the specimen
• d.Add a small amount of bleach to prevent bacterial growth

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

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.The tube color will fade and cause misidentification
• b.Vacuum and additive reactivity decline, so fill volume and results become unreliable✓
• c.Nothing, since expiration applies only to reagents
• 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.Shaking dissolves the stopper lubricant into the specimen
• c.Gentle inversion is required only for serum tubes
• d.Shaking causes mechanical hemolysis and foaming that invalidate many tests✓

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

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