Blutserum

Blutserum, or blood serum, is the liquid portion of blood that remains after the blood has clotted. It is produced by allowing a blood sample to coagulate and then centrifuging to separate the clot from the liquid. Unlike plasma, serum lacks fibrinogen and other clotting factors because they become part of the clot during coagulation.

Composition and distinction from plasma: Serum contains water, electrolytes, metabolites, hormones, and antibodies, as well as abundant proteins such as albumin and globulins. It does not contain fibrinogen or other coagulation factors, which are present in plasma. This difference makes serum particularly suitable for many diagnostic and research applications where these factors might interfere with analyses.

Applications: In clinical laboratories, serum is widely used for serological and immunological testing, including antibody detection, and for biochemical assays (hormones, enzymes, metabolites). Common techniques include ELISA, immunoassays, and biochemical panels. Serum is not used for red blood cell transfusion, since it is not a blood product intended for transfusion.

Handling and storage: Serum samples should be collected in appropriate tubes, allowed to clot, and then centrifuged to separate the liquid. They are typically stored frozen or refrigerated and may require avoidance of repeated freeze–thaw cycles to preserve analyte stability. Hemolyzed or contaminated samples can affect test results.

Variants and sources: In research and biotechnology, serum products such as fetal bovine serum (FBS) are used as supplements for cell culture. Human serum is also used in some diagnostic and research contexts, though its use requires careful ethical and regulatory consideration.