- Detection and assay of substances by serological (immunological) methods; in most applications the substance in question serves as antigen, both in antibody production and in measurement of antibody by the test substance. SEE ALSO: enzyme-linked immunosorbent assay, radioimmunoassay, radioimmunoelectrophoresis, immunologic pregnancy test. SYN: immunochemical assay.- enzyme i. any of several i. methods that use an enzyme covalently linked to an antigen or antibody as a label; the most common types are enzyme-linked immunosorbent assay (ELISA) and enzyme-multiplied i. technique (EMIT). SEE ALSO: enzyme-linked immunosorbent assay, enzyme-multiplied i. technique.- enzyme-multiplied i. technique (EMIT) a type of i. in which the ligand is labeled with an enzyme, and the enzyme-ligand-antibody complex is enzymatically inactive, allowing quantitation of unlabeled ligand. SEE ALSO: competitive binding assay, enzyme-linked immunosorbent assay.- solid phase i. i. in which the antigen or serum is bound to a solid surface, such as a microplate wall or the sides of a tube, the other reactants being free in solution.- thin-layer i. a method for detection of antigen-antibody reactions, applicable to detection of either antigen or antibody, based on the fact that either reactant, when added to a polystyrene surface (such as a well in a polystyrene plate) is adsorbed as a thin layer and acts as an immunosorbent capable of binding with the second reactant.
* * *im·mu·no·as·say .im-yə-nō-'as-.ā, im-.yü-nō-, -a-'sā n a technique or test (as the enzyme-linked immunosorbent assay) used to detect the presence or quantity of a substance (as a protein) based on its capacity to act as an antigen or antibodyimmunoassay vtim·mu·no·as·say·able -a-'sā-ə-bəl adj
* * *n.any of various techniques for determining the levels of antigen and antibody in a tissue. See immunoelectrophoresis, immunofluorescence, radioimmunoassay.
* * *im·mu·no·as·say (im″u-no-asґa) any of several methods for the quantitative determination of chemical substances that utilize the highly specific binding between an antigen or hapten and homologous antibodies, including radioimmunoassay, enzyme immunoassay, and fluorescence immunoassay.
Medical dictionary. 2011.