If you do not know, Enzyme Immunoassay (EIA) is actually a synonym for the ELISA.
ELISA, or rather known as Enzyme-Linked Immunosorbent Assay, is a rapid immunochemical test that involves an enzyme (a protein that catalyzes a biochemical reaction), an antibody or antigen (immunologic molecules).
ELISA serves as a method of quantitative determination of the amount of an antibody/antigen in a biological sample.
The principle of the experiment is based on the creation and the enzymatic evidence of antigen/antibody complexes fixed to a solid phase. The end product is soluble and can be gauged spectroscopically.
ELISA tests are widely utilized to detect substances that have antigenic properties, primarily proteins (as opposed to small molecules and ions such as glucose and potassium). Substances that can be detected by ELISA tests include hormones, bacterial antigens and antibodies.
Enzyme immunoassay (EIA) is a test used to detect and quantify specific antigen-eliciting molecules involved in biological processes, specifically processes related to cancer and autoimmune disorders.
EIA can be used on most types of biological samples, such as plasma, serum, urine, and cell extracts.
- In the assay, a plate is coated with a primary antibody, which recognizes the antigen of the target molecule and bonds with it.
- The antigen-antibody complex is recognized by a secondary antibody that is joined to an enzyme that catalyzes the reaction mixture, yielding a specific color.
- By measuring the optical density of this color, the presence and number of a specific molecule can be determined; the density of color is proportional to the advancement of the reaction or disease being tested.