What is Elisa principle and procedure?

The ELISA (Enzyme-Linked Immunosorbent Assay) principle involves the use of an enzyme-linked antibody to detect the presence of a specific antigen in a sample. The procedure typically includes coating a microplate with the antigen, blocking unoccupied sites, adding the sample to allow binding of the target antibody, and then adding an enzyme-linked secondary antibody that binds to the primary antibody. After washing to remove unbound components, a substrate for the enzyme is added, resulting in a detectable signal, often a color change, which is proportional to the amount of antigen present.