Difference between Plasma & Serum. ( & Anticoagulant )

Plasma consists of fibrinogen/clotting factor. It is the cells-free part of the blood which can be collected by spinning the red capped test tube that containing the blood until the blood cells have sediment at the bottom. The blood is often treated with anticoagulant before centrifuge.

Serum is the plasma without the clotting factors.
It can be obtained by centrifuge the blood sample after the blood is clotted in the SST tube.

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Anticoagulant

• Function: Block the formation of fibrin clot.

• Examples:
• EDTA
• Potassium Oxalate
• Sodium Citrate

• Mechanism: Removal of Ca++ which is essential for the conversion of prothrombin to thrombin.                       [Thrombin is the enzyme that initiate the conversion of fibrinogen to fibrin]