NHA Certified Phlebotomy Technician (CPT)Specimen HandlingMedium
A phlebotomy technician needs to prepare a complete blood count (CBC) specimen for transport to an off-site lab. Which of the following is the most appropriate storage condition for this specimen?
- AIncubated at 37°C (98.6°F).
- BFrozen at -20°C (-4°F).
- CRefrigerated at 2°C to 10°C (35.6°F to 50°F).
- DStored at room temperature (18°C to 25°C / 64°F to 77°F).
Show answer & explanationAnswer & explanation
Correct answer: C. Refrigerated at 2°C to 10°C (35.6°F to 50°F).
CBC specimens collected in EDTA tubes are stable for up to 24 hours when refrigerated at 2°C to 10°C. Freezing can cause hemolysis and cellular damage, while room temperature storage beyond a few hours can lead to cellular degradation and inaccurate results.
Why the other options are wrong
- A. Incubation at body temperature would accelerate cellular metabolism and degradation, rapidly compromising the specimen's integrity.
- B. Freezing causes red blood cell lysis and cellular damage, making the specimen unsuitable for CBC analysis.
- D. Storing at room temperature for extended periods (beyond a few hours) can lead to changes in cell size, morphology, and degradation of cellular components, affecting CBC results.
CBC Specimen Storage
Complete blood count (CBC) specimens collected in EDTA tubes are stable for a limited time. Refrigeration is the preferred method for storage if testing is delayed, as it slows down cellular degradation without causing damage.
- Collected in lavender-top (EDTA) tube.
- Stable for up to 24 hours when refrigerated.
- Room temperature storage for >2-4 hours can alter results.
- Freezing is contraindicated due to cell lysis.
Memory trick: CBC cells like it cool, not frozen, not warm, that's the golden rule.