(RIA), uses fixed-dose, low-level, radioactive-isotope-labeled antigen ("tracer") to compete with unlabeled antigen from the patient specimen for a fixed number of antibody binding sites. Traditional RIA is done with specific antibodies in liquid solution. Solid-phase RIA involves the use of antibody bound to solid support (e.g., tubes, glass beads or plastic fins). The amount of antigen in the specimen is determined by comparing the bound radioactivity with a standard curve.
A special type of in vitro procedure that combines the use of radiochemicals and antibodies to measure the levels of hormones, vitamins and drugs in a patient's blood.
(Abbreviation: RIA) An assay based on the use of a radioactively labelled antibody, where the amount of radiation detected indicates the amount of target substance present in the sample.
immunoassay of a substance that has been radioactively labeled
a procedure for detecting antigens or antibodies using radioactive-labeled complement proteins.
A diagnostic test using antibodies to detect trace amounts of substances. Such tests are useful in biomedical research to study how drugs interact with their receptors.
A widely used technique for measurement of primary antigen-antibody interactions, and for the determination of the level of important biological substances in mixed samples. It takes advantage of the specificity of the antigen-antibody interaction and the sensitivity that derives from measurement of radioactively labelled materials.
Radioimmunoassay (RIA) is a scientific method used to test antigens (for example, hormone levels in the blood) without the need to use a bioassay. It involves mixing known quantities of radioactive antigen (frequently labeled with gamma-radioactive isotopes of iodine attached to tyrosine) with antibody to that antigen, then adding unlabeled or "cold" antigen and measuring the amount of labeled antigen displaced.
