Which additive do PST tubes contain to aid plasma separation?

Which additive do PST tubes contain to aid plasma separation?

• A. Gel separator in PST tubes
• B. Gel separator not present in PST tubes
• C. PST tubes contain EDTA
• D. PST tubes do not separate plasma after centrifugation

Answer: (A)

PST tubes use a gel separator to create a physical barrier between plasma and the cellular elements after centrifugation, giving a clean plasma layer for testing. The gel moves to the interface due to density differences, keeping cells below and plasma above. PST tubes are also anticoagulated (typically with lithium heparin) to prevent clotting, but the feature that aids separation is the gel separator. So, the additive that PST tubes contain to aid plasma separation is the gel separator. The other options don’t fit because PST tubes do include a gel separator; EDTA is not the additive in PST tubes, and these tubes are designed to separate plasma after centrifugation.

PST tubes use a gel separator to create a physical barrier between plasma and the cellular elements after centrifugation, giving a clean plasma layer for testing. The gel moves to the interface due to density differences, keeping cells below and plasma above. PST tubes are also anticoagulated (typically with lithium heparin) to prevent clotting, but the feature that aids separation is the gel separator. So, the additive that PST tubes contain to aid plasma separation is the gel separator. The other options don’t fit because PST tubes do include a gel separator; EDTA is not the additive in PST tubes, and these tubes are designed to separate plasma after centrifugation.