Skip to content

plasma and serum preparation


benchmark antibodies

Plasma and Serum preparation protocol

How to Extract Serum and Plasma from Blood

Serum, the liquid portion of whole blood obtained after allowing blood to clot, involves the removal of the clot through centrifugation. The resulting supernatant, referred to as serum, is meticulously extracted using a Pasteur pipette. In contrast, plasma is derived when blood is collected in anticoagulant-treated tubes, preventing clotting. After centrifugation removes cells, the supernatant, designated as plasma, is carefully separated from the cell pellet using a Pasteur pipette.

Serum Preparation

  1. Collect whole blood in a covered test tube, preferably red-topped tubes from Becton Dickinson (BD).
  2. Allow the blood to clot by leaving it undisturbed at room temperature for 15–30 minutes.
  3. Remove the clot through centrifugation at 1,000–2,000 x g for 10 minutes in a refrigerated centrifuge.
  4. Immediately transfer the resulting supernatant (serum) into a clean polypropylene tube using a Pasteur pipette.
  5. Maintain samples at 2–8°C during handling.
  6. If not analyzed immediately, apportion serum into 0.5 ml aliquots and store at –20°C or lower to avoid freeze-thaw cycles.
  7. Hemolyzed, icteric, or lipemic samples can invalidate certain tests.

Plasma Preparation

  1. Collect whole blood in commercially available anticoagulant-treated tubes (e.g., EDTA-treated lavender tops or citrate-treated light blue tops).
  2. Centrifuge for 10 minutes at 1,000–2,000 x g using a refrigerated centrifuge to remove cells.
  3. Transfer resulting plasma supernatant into a clean polypropylene tube using a Pasteur pipette.
  4. Maintain samples at 2–8°C during handling.
  5. If not analyzed immediately, apportion plasma into 0.5 ml aliquots and store at –20°C or lower to avoid freeze-thaw cycles.
  6. Hemolyzed, icteric, or lipemic samples can invalidate certain tests.

Serum and Plasma Tubes

Commercially available serum tubes:

  • Red: No anticoagulant.
  • Red with black: Treated with gel to aid clot separation (not evaluated).

Commercially available plasma tubes:

  • Lavender: Treated with EDTA.
  • Blue: Treated with citrate.
  • Green: Treated with heparin.
  • Grey: Treated with potassium oxalate/sodium fluoride (not evaluated).
  • Yellow: Treated with potassium oxalate/sodium fluoride (not evaluated).

Remember to always refer to the specific protocols and recommendations provided by the manufacturers of the reagents and equipment you are using, as they may have specific instructions or variations for their products.