Plasma Separating Tubes These tubes contain ethylenediaminetetraacetic acid
(EDTA) which is a strong anticoagulant. The tubes should be inverted several
times after sample collection.
Procedure for Plasma Preparation
Draw blood from patient and pour it in vacutainer with an appropriate anticoagulant.
Mix blood with anticoagulant properly and allow the tubes to stand for 10 min. Then,
the sample is centrifuged for speed separation and packing of cells. The supernatant
is the plasma.
Serum Serum composition is the same as that of plasma except that serum lacks
fibrinogen.
- For many laboratory biochemical tests, plasma and serum both can be used
interchangeably.
Procedure for Serum Preparation
- Draw blood from patient. Select vacutainer without anticoagulant.
- Allow the vacutainer to stand for 20–30 min so that clot is formed.
- Centrifuge the sample at 3000 rpm which affects a greater packing of cells.
Various cells along with clot will settle in the form of pellet at the bottom of
the tube. - The supernatant is the serum.
Fig. 2.1 Vacutainers used for
blood collection and storage
6 2 Blood Collection and Preservation