In Vitro Tests

The radioimmunoassay (RIA) method was first developed by S. A. Berson and R. S. Yallow in the late 1950s for the determination of insulin in human serum. Presently, the method is employed extensively to determine numerous hormones, enzymes, and drugs in minute quantities (10-9–10-12 M) in human plasma in order to assess various disease conditions. The general term for this method in both immune and nonimmune systems is the competitive binding assay (CBA).