NHA Certified Phlebotomy Technician (CPT)Specimen HandlingMedium
A phlebotomy technician is preparing to transport a 24-hour urine specimen for creatinine clearance. Which of the following instructions should be reinforced to the patient regarding its storage during collection?
- ADiscard the first morning void on the second day of collection.
- BAdd a preservative tablet to the container every 6 hours.
- CKeep the specimen at room temperature throughout the collection period.
- DStore the specimen in a dark, cool place, preferably refrigerated.
Show answer & explanationAnswer & explanation
Correct answer: D. Store the specimen in a dark, cool place, preferably refrigerated.
24-hour urine specimens, especially for creatinine clearance, must be kept refrigerated or on ice during the entire collection period to prevent bacterial overgrowth and degradation of analytes. This helps maintain specimen integrity.
Why the other options are wrong
- A. The first morning void on the second day is typically the LAST void collected for a 24-hour specimen, not discarded. The first void on day 1 is discarded.
- B. Preservatives are sometimes used, but the instruction is usually given by the lab, and 'every 6 hours' is not standard; refrigeration is a more universal requirement.
- C. Room temperature storage for 24 hours can lead to significant bacterial growth and degradation of analytes, invalidating the specimen.
24-Hour Urine Storage
24-hour urine specimens require refrigeration or storage on ice throughout the collection period to preserve analytes and prevent microbial contamination.
- Refrigerate or keep on ice.
- Prevents bacterial growth.
- Maintains analyte stability.
Memory trick: 24 hours of urine needs a 'cool' attitude.