Enzyme linked immunosorbent assays (ELISA), also known as enzyme immunoassays (EIA), are tests designed to detect antigens or antibodies by producing an enzyme triggered color change. All of the EIAs performed in the Diagnostic Serology Section are known as solid-phase assays.
Radioimmunoassay (RIA)) Radioimmunoassay (RIA) Radioimmunoassay (RIA) is an in vitro assay that measures the presence of an antigen with very high sensitivity. Basically any biological substance for which a specific antibody exists can be measured, even in minute concentrations. RIA has been the first immunoassay technique developed to analyze nanomolar and picomolar concentrations of hormones in biological fluids.