Introduction

Separating serum and plasma from blood involves distinct processes. Serum is the liquid fraction of whole blood collected after allowing the blood to clot. The clot is removed through centrifugation, and the resulting supernatant, designated as serum, is carefully extracted using a Pasteur pipette. Plasma is produced when whole blood is collected in tubes treated with an anticoagulant. In these tubes, the blood does not clot. The cells are removed by centrifugation, and the supernatant, designated as plasma, is carefully extracted from the cell pellet using a Pasteur pipette. These methods are crucial for various diagnostic and research applications.

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Blood serum preparation

Materials

  • Serum tubes

The commercially available serum tubes are as follows:
Red
No anticoagulant.
Red with black
Treated with gel to help to separate the clot.

Procedure

  1. Collect whole blood in a covered test tube. If you are using commercially available tubes, please use the red top tubes.
  1. Allow the blood to clot by leaving it undisturbed at room temperature. This usually takes 15–30 minutes.
  1. Remove the clot by centrifugation at 1,000–2,000 x g for 10 minutes in a refrigerated centrifuge. The resulting supernatant is designated as serum. 
  1. Immediately transfer the supernatant (serum) into a clean polypropylene tube using a Pasteur pipette. The samples should be maintained at 2–8°C while handling.
  1. If the serum is not analyzed immediately, aliquot into 0.5 mL portions, and store and transport at –20°C or lower. Avoid freeze-thaw cycles. 

Note:Samples which are hemolyzed, icteric, or lipemic can invalidate certain tests.


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Blood plasma preparation

Materials

  • Plasma tubes

The commercially available plasma tubes are as follows: 
Lavender
Treated with EDTA.
Blue
Treated with citrate.
Green
Treated with heparin.
Grey
Treated with potassium oxalate/sodium fluoride.
Yellow
Treated with potassium oxalate/sodium fluoride.

Procedure

  1. Collect whole blood into commercially available anticoagulant-treated tubes, e.g., EDTA-treated (lavender tops) or citrate-treated (light blue tops).

    Note:    Heparinized tubes (green tops) can be used for some applications, however be aware that heparin can be contaminated with endotoxin, which may stimulate white blood cells to release cytokines.
  1. Remove cells from plasma by centrifugation at 1,000–2,000 x g for 10 minutes in a refrigerated centrifuge. For platelet depletion in the plasma sample, centrifuge at 2,000 x g for 15 minutes. The resulting supernatant is designated as plasma.
  1. Immediately transfer the supernatant (serum) into a clean polypropylene tube using a Pasteur pipette. Maintain samples at 2–8°C while handling.
  1. If plasma is not analyzed immediately, aliquot into 0.5 mL portions, and store and transport at –20°C or lower. Avoid freeze-thaw cycles.

Note: Hemolyzed, icteric, or lipemic samples can invalidate certain tests.

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Stylesheet for Classic Wide Template adjustments

For Research Use Only. Not for use in diagnostic procedures.