The thixotropic gel in PST tubes creates what apart from plasma?

The thixotropic gel in PST tubes creates what apart from plasma?

• A. It acts as an anticoagulant
• B. A barrier between plasma and cells after centrifugation
• C. It binds calcium
• D. It lyses cells

Answer: (B)

The key idea is that the gel in PST tubes acts as a physical separator after centrifugation. When spun, the thixotropic gel settles between the plasma on top and the cellular components below, forming a distinct barrier that keeps the plasma separate from the cells. This barrier helps prevent contact between plasma and cells, preserving sample quality for testing. The gel itself isn’t an anticoagulant, doesn’t bind calcium, and doesn’t lyse cells; its job is simply to create that clear separation layer.

The key idea is that the gel in PST tubes acts as a physical separator after centrifugation. When spun, the thixotropic gel settles between the plasma on top and the cellular components below, forming a distinct barrier that keeps the plasma separate from the cells. This barrier helps prevent contact between plasma and cells, preserving sample quality for testing. The gel itself isn’t an anticoagulant, doesn’t bind calcium, and doesn’t lyse cells; its job is simply to create that clear separation layer.