ELISA

Enzyme-linked immunosorbent assay (ELISA), is a common method which based on an enzymatic colour reaction. The test is used to detect the presence of an antibody or an antigen (virus, proteins or hormones) in a sample.

The principle which is used for this test is an antibody-antigen-reaction. For the detection of proteins the adequate antibodies should be known. The antibody as well as the antigen is linked to an enzyme, which catalyzed a reaction. This reaction shows the presence of the antigen and leads to a detectable signal (colour reaction). The intensity of the signal is direct proportional to the antigen concentration. So ELISA test method can also be used for quantitative detections.