- During aliquoting of pediatric specimens with limited volume, a technician has 0.8 mL of serum available. The ordered tests require: CBC (0.3 mL), comprehensive metabolic panel (0.4 mL), and thyroid function (0.3 mL). What is the best approach to maximize test completion?
Answer: Contact the laboratory supervisor to determine which tests have micro-methods available before proceeding
Many pediatric laboratories offer micro-methods that require significantly less specimen volume. Determining availability before aliquoting prevents waste and may allow completion of all tests. Choice A arbitrarily prioritizes tests without exploring volume-reduction options. Choice B may provide insufficient volume for accurate results. Choice D eliminates potentially critical tests without exploring alternatives.
- A technician is preparing aliquots from plasma tubes for coagulation studies. The laboratory protocol requires maintaining the cold chain at 2-8°C during processing. After centrifugation, which step should be completed first to ensure specimen integrity?
Answer: Place centrifuged tubes on ice and complete all labeling of aliquot tubes before beginning plasma transfer
For coagulation studies requiring cold chain maintenance, preparation should minimize time at non-optimal temperatures. Completing labeling first while tubes are on ice ensures rapid processing once aliquoting begins. Choice A involves too much time in refrigerated environment which may be impractical. Choice B breaks the cold chain unnecessarily. Choice C would compromise temperature-sensitive coagulation factors that degrade rapidly at room temperature.
- SST spun 5 min; no gel barrier formed. Next step?
Answer: Recap and re-spin 10 min
A 5-minute spin can be too short for the gel to migrate, so you can safely recap the SST and re-spin for 10 minutes. The tempting wrong move is to discard and redraw, but that is only needed if the barrier still fails after a full recommended spin. Pouring into a plain tube removes the gel separator, and shaking can cause hemolysis.
- No-gel red top spun; where should pipet tip go?
Answer: Near surface, above cell layer
In a spun no-gel red top tube, the serum is the top layer and the cells/clot settle below. Place the pipet tip near the surface, well above the cell layer, so you aspirate only serum and don't pull in cells or fibrin at the interface. The tempting choice is the serum-cell interface, but that risks contaminating the sample with cellular material.
- When aliquoting specimens for research protocols with strict volume requirements, a technician discovers that centrifugation of a 10 mL red-top tube yielded only 3.2 mL of serum instead of the expected 5.5 mL. The tube appeared properly filled initially. What is the most likely explanation?
Answer: The patient's hematocrit was significantly elevated, resulting in reduced plasma volume and increased cellular mass
A properly filled 10 mL tube typically yields 50-55% serum (5-5.5 mL). Yielding only 3.2 mL (32%) suggests elevated hematocrit, where increased red blood cell mass leaves less plasma volume. Choice A would cause color change but not dramatic volume reduction. Choice B affects clot quality but wouldn't reduce total serum volume this significantly. Choice D would be minimal over typical clotting times and wouldn't account for this degree of volume loss.
- A technician observes lipemia in a serum specimen during aliquoting for lipid profile testing. The patient was reportedly fasting for 12 hours. Which factor should be investigated first to determine the cause?
Answer: Verify the actual duration and completeness of the patient's fasting status including beverages consumed
Lipemia in a supposedly fasting specimen most commonly indicates incomplete fasting compliance. Patients may not understand that cream in coffee, certain medications, or recent meals can cause lipemia. Choice B relates to hemolysis, not lipemia. Choice C affects separation quality but not lipemic appearance. Choice D would affect clotting but not lipid content in serum.
- Unlabeled aliquot found; original SST remains. Action?
Answer: Discard; re-aliquot original
An unlabeled aliquot cannot be linked to a specific patient, so labeling it from the original tube assumes a match you cannot verify. Discard the unlabeled aliquot and prepare a fresh, labeled aliquot directly from the original SST. Labeling from the original tube is tempting because it seems efficient, but it risks misidentification and violates specimen integrity rules.
- When preparing aliquots for frozen storage at -20°C, a technician must process 15 serum specimens for hormone analysis. The laboratory protocol specifies that aliquots should be frozen within 4 hours of collection. Which approach best ensures specimen integrity?
Answer: Process specimens in order of collection time, prioritizing those approaching the 4-hour deadline regardless of batch size
Time from collection is the critical factor for hormone stability. Processing by collection time ensures no specimen exceeds the 4-hour stability window. Choice A ignores individual specimen timing requirements. Choice B uses arbitrary batching that may cause some specimens to exceed time limits. Choice C prioritizes freezer temperature over specimen stability requirements, potentially compromising analyte integrity.
- A phlebotomy technician needs to prepare aliquots from a 7 mL serum tube for multiple tests. The chemistry panel requires 2.5 mL, the immunology tests need 1.8 mL, and the endocrinology tests require 1.2 mL. After centrifugation, the tube yields 3.8 mL of serum. What is the most appropriate action?
Answer: Contact the ordering physician to determine test priority and proceed with recollection for insufficient volume
The total serum needed (5.5 mL) exceeds the available volume (3.8 mL) by 1.7 mL. This represents a significant shortfall that cannot be resolved by proportional distribution or test combining without potentially compromising test accuracy. The appropriate action is to contact the ordering physician to establish priorities and arrange recollection. Choice A would provide insufficient volume for accurate testing. Choice B still leaves insufficient volume for some tests. Choice D could compromise test integrity by mixing incompatible specimens.
- During aliquoting of specimens for send-out testing, a technician notices that one serum tube has developed a fibrin clot after centrifugation. The tube was properly filled and mixed initially. What is the most likely cause and appropriate response?
Answer: Inadequate clotting time before centrifugation; re-centrifuge the tube at higher speed to break up fibrin strands
Fibrin clots appearing after centrifugation indicate incomplete coagulation before processing, often due to insufficient clotting time (typically 30-60 minutes required). Re-centrifugation can help compact remaining fibrin. Choice B would contaminate the specimen and filtering is not appropriate. Choice C would disrupt the clot and worsen the problem. Choice D risks fibrin contamination of aliquots and potential instrument clogging.
- A technician is aliquoting plasma specimens for send-out testing that requires shipping at ambient temperature. The specimens will be in transit for 36 hours. Which pre-analytical factor most significantly impacts specimen stability during this timeframe?
Answer: The time elapsed between collection and completion of the aliquoting process before shipping
For 36-hour ambient transport, minimizing pre-shipping processing time is critical because analyte degradation begins immediately after collection. Rapid processing and aliquoting preserve specimen integrity before the extended transport period. Choice A affects initial specimen quality but not transport stability. Choice C has minimal impact on most analytes during ambient transport. Choice D becomes relevant but is secondary to minimizing total time from collection to analysis.
- A laboratory processes 50 specimens daily requiring aliquoting for multiple departments. To maintain proper chain of custody during this process, which documentation element is most critical?
Answer: Maintaining a log that traces each aliquot back to the original specimen with unique identifier linkage
Chain of custody requires maintaining an unbroken link between original specimens and all derivatives. Each aliquot must be traceable back to its source specimen through unique identifiers. Choice A documents process details but not custody linkage. Choice C relates to technical procedures, not custody. Choice D shows workflow but doesn't establish the critical specimen-to-aliquot relationship required for chain of custody.
- Plain red top spun before clotting finished. Expect?
Answer: Fibrin strands in serum
Spinning a plain red top before the clot has fully formed leaves fibrin strands suspended in the serum, so you'd see them after centrifugation. The most tempting wrong answer is a gel barrier at bottom, but a plain red top has no gel separator. Hemolysis and an absent serum layer are not expected from early spinning.
- After spinning a gel tube, how do you aliquot serum?
Answer: Pipet serum from above the gel
After spinning, the gel forms a barrier between the serum on top and the cells below. Pipetting from above the gel safely removes serum without cell contamination. Pouring into a plain tube is tempting, but it can disturb the gel and allow cells to mix into the serum.
- When aliquoting serum for therapeutic drug monitoring, a technician observes that the primary tube contains visible hemolysis. The original specimen was collected in a gold-top SST tube and properly centrifuged. Which factor most likely contributed to this pre-analytical error?
Answer: Improper needle gauge selection during the original venipuncture procedure causing cellular damage
Hemolysis visible during aliquoting typically results from mechanical trauma during collection, most commonly from using too small a needle gauge (>22G) or excessive vacuum pressure causing red blood cell lysis. Choice A would result in cellular contamination, not hemolysis. Choice B would cause foam but not significant hemolysis in properly separated serum. Choice D would affect clot quality but not necessarily cause hemolysis visible during aliquoting.
