Theme 5- METHODS OF PREPARATION OF BLOOD SERUM AND PLASMA

Question 1

What is serum and plasma

Answer 1

-Serum is the liquid fraction of whole blood that is collected after the blood is allowed to clot. The clot is removed by centrifugation and
the resulting supernatant, designated serum, is carefully removed.

-Meanwhile, plasma is produced when whole blood is collected in tubes that are treated with an anticoagulant.

Question 2

Serum preparation

Answer 2

1) Collect whole blood in a covered test tube.
2) After collection of the whole blood, allow
the blood to clot by leaving it undisturbed at room temperature. This usually takes 30
minutes and no more than one hour.
3) Remove the clot by centrifuging at 1,000-2,000 x g (3000 – 5000 rotations per minute) for 10 minutes.
4) The resulting supernatant is designated serum.
5) Following centrifugation, it is important to immediately transfer the liquid component (serum) into a clean polypropylene tube using a pipette.
6)The samples should be maintained at 2-8°C while handling.
7) If the serum is not analysed immediately, the serum should be stored and transported at -20°C or lower.
8) It is important to avoid or at least minimize freeze-thaw cycles because this is detrimental
to many serum components.

Question 3

Plasma preparation

Answer 3

1) Collect whole blood into tubes with the anticoagulant EDTA.
2) Cells are removed from the plasma by centrifugation for 10 minutes at 1,000-2,000 x g (3000 – 5000 rotations
per minute).
3) Centrifugation for 15 minutes at 2,000 x g depletes platelets in the plasma sample. The resulting supernatant is designated plasma.
4) Following centrifugation, it is important to immediately transfer the plasma into a clean
polypropylene tube using a pipette.
5) The samples should be maintained at 2-8°C while handling.
6) If the plasma is not analyzed immediately, the plasma should be stored and transported at –20°C or lower.