immunoassay

A ligand-binding assay that uses a specific antigen or antibody, capable of binding to the analyte, to identify and quantify substances. The antibody can be linked to a radiosotope (radioimmunoassay, RIA), or to an enzyme which catalyses an easily monitored reaction (enzyme-linked immunosorbent assay, ELISA), or to a highly fluorescent compound by which the location of an antigen can be visualized (immunofluorescene).
Source:
PAC, 1992, 64, 143 (Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992)) on page 157
PAC, 1994, 66, 2513 (Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)) on page 2520