What is the purpose of the thixotropic gel found in SST tubes?

What is the purpose of the thixotropic gel found in SST tubes?

• A. It Thickens the Sample
• B. It Forms a Barrier Between Blood Cells and Serum/Plasma to Prevent Contamination
• C. It Acts as an Anticoagulant
• D. It Speeds Up Clotting

Answer: (B)

The main idea is that the thixotropic gel in SST tubes acts as a physical barrier that forms between the serum (the liquid part after clotting) and the blood cells once the sample is centrifuged. This barrier keeps cellular components from mixing back into the serum, which helps prevent contamination and interference with test results. The gel is inert and moves to sit between the clot and the serum during spinning, so it doesn’t participate in clotting or alter the chemistry of the serum. It’s not an anticoagulant, and it doesn’t speed up clotting—the clot activator in the tube handles clotting, while the gel’s job is clean separation.

The main idea is that the thixotropic gel in SST tubes acts as a physical barrier that forms between the serum (the liquid part after clotting) and the blood cells once the sample is centrifuged. This barrier keeps cellular components from mixing back into the serum, which helps prevent contamination and interference with test results. The gel is inert and moves to sit between the clot and the serum during spinning, so it doesn’t participate in clotting or alter the chemistry of the serum. It’s not an anticoagulant, and it doesn’t speed up clotting—the clot activator in the tube handles clotting, while the gel’s job is clean separation.