Plasma versus serum
From WikiLectures
Plasma and serum are obtained by taking venous blood.
Plasma[edit | edit source]
Plasma together with blood cells and elements form blood. We get it from non-coagulating whole blood. In order for the blood in the collection system not to "clot", we must prevent hemocoagulation:
- by binding of Ca 2+ ions:
- anion of a weak acid (citrate, oxalate,…) and salts that do not dissociate are formed;
- as well as a chelating agent (EDTA) to form chelate;
- surface treatment of the material of the sampling system (heparin coating).
Finally, we remove cells and cellular elements by centrifugation.
Serum[edit | edit source]
Obtaining serum is not so complicated - we do not prevent hemocoagulation in a collection system that often contains crystals to increase the contact surface. There is hemocoagulation, a fibrin network is formed in which blood cells are also trapped. What remains "liquid" is called serum.
Centrifugation is therefore no longer necessary.
Comparison[edit | edit source]
| plasma | serum | |
|---|---|---|
| Cells and elements | no | no |
| Proteins excluding coagulation factors | yes | yes |
| Coagulation factors | yes | no |
| Degradation products of coagulation factors | no | yes |
