Definition - What does Epitope mean?
An epitope is the portion of an antigen to which the immune system, specifically antibodies, react to and bind with in order to complete the immune response. An epitope, and the action by which it bonds to antibodies, plays a vital role in the detection of drug metabolites in immunoassay drug screening. An epitope is also called an antigenic determinant.
WorkplaceTesting explains Epitope
In terms of immunoassay drug screening, antibodies are classified by the epitope they bond to. Specifically, it is the binding action of the epitope to the particular antibody that identifies the antibody. In revealing the specific antibody, the presence of drug metabolites is also uncovered. This does not reveal the specific drug present, but merely the presence of metabolites that fall under certain classes of drugs. For this reason, immunoassay drug screening tests can only yield positive or negative results that signify the presence or absence of drug metabolites.