59. 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 × and then set for 30 min prior to centrifugation.
To ensure optimal test results when collecting 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.
A) Invert the tube 5 to 8 × 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 and the gel separator, which is crucial for proper serum separation. Additionally, allowing the tube to sit for 30 minutes provides sufficient time for the blood to clot before centrifugation, leading to accurate test results.
B) Invert the tube 1 to 3 × and then set for 1 hr prior to centrifugation.
This option is incorrect as inverting the tube only 1 to 3 times may not provide enough mixing of the gel and blood, potentially affecting serum separation. Moreover, setting the tube for 1 hour before centrifugation exceeds the recommended waiting time and could lead to changes in the sample quality.
C) Invert the tube 2 to 4 × and then set for 15 min prior to centrifugation.
This option is also incorrect. Inverting the tube only 2 to 4 times does not adequately mix the components, which can compromise serum separation. Furthermore, a 15-minute wait is insufficient for proper clot formation, possibly resulting in hemolysis or incomplete separation.
D) Invert the tube 8 to 10 × and then set for 2 hr prior to centrifugation.
This option is incorrect because although inverting the tube 8 to 10 times is appropriate for mixing, waiting for 2 hours is excessive. This prolonged time could lead to degradation of the sample or other alterations that may affect test results.
Conclusion
Option A is the optimal choice as it provides the correct balance of mixing and waiting time to ensure proper serum separation. The other options either fail to mix adequately, wait too long, or provide insufficient time for clotting, which can negatively impact the accuracy of the test results.