21. When a serum separation tube (SST) is collected, which of the following actions should the phlebotomist take to ensure optimal test results?
Answer: A
Invert the tube 5 to 8 times and then set for 30 min prior to centrifugation.
To ensure optimal test results when using a serum separation tube (SST), the phlebotomist should invert the tube 5 to 8 times and then allow it to sit for 30 minutes before centrifugation. This process helps to properly mix the blood with the gel separator and facilitates serum separation.
A) Invert the tube 5 to 8 times and then set for 30 min prior to centrifugation.
This option is correct because inverting the tube 5 to 8 times ensures adequate mixing of the blood with the clot activator and gel, which is essential for effective serum separation. Allowing the tube to sit for 30 minutes also provides sufficient time for the clot to form before centrifugation, leading to optimal test results.
B) Invert the tube 1 to 3 times and then set for 1 hr prior to centrifugation.
This option is incorrect because inverting the tube only 1 to 3 times may not adequately mix the blood with the clot activator and gel. Additionally, setting the tube for 1 hour is excessive and could lead to changes in the serum that may affect test results.
C) Invert the tube 2 to 4 times and then set for 15 min prior to centrifugation.
This option is also incorrect. Inverting the tube 2 to 4 times may not provide sufficient mixing compared to the recommended 5 to 8 times. Furthermore, a 15-minute wait is too short for the clot to adequately form before centrifugation.
D) Invert the tube 8 to 10 times and then set for 2 hr prior to centrifugation.
This option is incorrect as well, despite the inversion being in the correct range. However, allowing the tube to sit for 2 hours is unnecessary and could compromise the integrity of the sample, potentially leading to inaccurate test results.
Conclusion
The correct procedure for handling a serum separation tube is to invert it 5 to 8 times and allow it to sit for 30 minutes prior to centrifugation. This method ensures proper mixing and clot formation, which are critical for obtaining reliable laboratory results. Other options either insufficiently mix the sample or allow for an inappropriate waiting period, jeopardizing the quality of the test outcomes.