Is EIA the competition of RIA

The principle and theoretical basis of enzyme-immunoassay (EIA) methods ELISE (enzyme-linked immunosorbent assay), CELIA (competitive enzyme-linked immunoassay), EMIT (enzyme multiplied immunoassay technique) and practical experiences with determination of digoxin level in blood by EMIT digoxin assay manual kit from Syva Corp. are described. The most important part of every mentioned procedure is antiqen ensyme labelling. The activation of this binding reaction is achieved through the action of glutaraldehyde. The enzymes currently used for labelling are: peroxidase, beta-galactosidase, alkaline phosphatase, malate dehydrogenase, glucose-oxidase, glucoamylase, acetylcholinesterase and lysozyme. To simplify the procedure substrates are used, which give color reaction immediately after splitting. The radioimmunoassay methods will remain the method of choice for determination of special substances in biologic material and substances with very low concentrations. (T.I.)