An immunoassay is a biochemical test that measures the presence or concentration of a macromolecule or a small molecule in a solution through the use of an antibody. Immunoassays are highly specific tests that rely on the inherent ability of an antibody to recognize and bind a specific macromolecule in a complex mixture of macromolecules. The analyte, which is the molecule being measured, can be a small molecule, such as a toxin or hormone, or a larger molecule, such as a protein or a virus.
There are different types of immunoassays, including enzyme immunoassays (ELISAs), radioimmunoassays (RIAs), and chemiluminescence immunoassays (CLIAs) . In ELISAs, for example, the analyte is coated onto a plate and used to bind antibodies found in a sample. When the sample is added, the antigen on the plate is bound by antibodies from the sample, which are then retained in the well. A species-specific antibody labeled with HRP is added next, which binds to the antibody bound to the antigen on the plate. The higher the signal, the more antibodies there are in the sample.
Immunoassays have a wide range of applications in various fields, including clinical diagnostics, drug monitoring, biopharmaceutical analysis, and environmental monitoring. They are easy to perform and can be used on-site or in the laboratory to detect specific molecules.
