NHA Certified Phlebotomy Technician (CPT)Specimen HandlingMedium
A phlebotomy technician needs to separate plasma from cells for a routine coagulation test (e.g., PT/INR). What is the maximum recommended time to centrifuge the specimen after collection if it is not spun immediately?
- A2 hours
- B1 hour
- C15 minutes
- D30 minutes
Show answer & explanationAnswer & explanation
Correct answer: B. 1 hour
For routine coagulation tests, if not centrifuged immediately, plasma should be separated from cells within 1 hour of collection. This minimizes the impact of cellular metabolism on test results and maintains analyte stability.
Why the other options are wrong
- A. 2 hours is generally too long for routine coagulation tests, as it can lead to degradation of labile factors and affect results.
- C. While ideal to spin sooner, 15 minutes is not the maximum recommended time.
- D. 30 minutes is a good target, but 1 hour is often cited as the acceptable maximum for routine coagulation.
Coagulation Specimen Centrifugation Time
For routine coagulation tests like PT/INR, plasma must be separated from cellular components within a specific timeframe after collection to preserve the integrity and stability of coagulation factors.
- Crucial for PT/INR, PTT tests.
- Prevents cellular metabolism from affecting results.
- Recommended within 1 hour of collection.
- Centrifuge at 1500g for 10-15 minutes.
Memory trick: Coagulation factors degrade fast, so spin within an hour, or results won't last.