NHA Certified Phlebotomy Technician (CPT)Specimen HandlingHard
A phlebotomy technician is preparing to send a frozen plasma specimen to a reference laboratory. Which of the following conditions is most likely to compromise the specimen's integrity during transport?
- AGentle agitation during transit.
- BExposure to bright light.
- CThawing and refreezing.
- DFluctuations in room temperature.
Show answer & explanationAnswer & explanation
Correct answer: C. Thawing and refreezing.
Thawing and refreezing of a frozen specimen, especially plasma, can lead to degradation of labile analytes, protein denaturation, and precipitation. This significantly compromises the specimen's integrity and can render it unsuitable for testing.
Why the other options are wrong
- A. Gentle agitation is generally not harmful to frozen specimens; vigorous shaking of thawed specimens can cause hemolysis, but not typically a frozen one.
- B. While some analytes are light-sensitive, a frozen plasma specimen is less likely to be compromised by light than by temperature changes.
- D. Fluctuations in room temperature can cause thawing, but the act of thawing and refreezing is the direct cause of degradation, not just the temperature fluctuation itself.
Frozen Specimen Integrity
Maintaining a consistently frozen state is paramount for frozen specimens during transport and storage. Any thawing and subsequent refreezing can severely degrade analytes, leading to inaccurate test results.
- Avoids degradation of labile analytes.
- Prevents protein denaturation and precipitation.
- Use dry ice or specialized frozen transport containers.
- One thaw cycle is generally acceptable; refreezing is not.
Memory trick: Once frozen, stay frozen; thaw and refreeze, and the results will be broken.