radioimmunoassay
Noun A highly sensitive laboratory technique used to measure minute concentrations of substances (such as hormones, drugs, or vitamins) in a sample of blood or other fluid. It combines the specificity of an immunological reaction (using antibodies) with the sensitivity of radiation measurement by employing a radioactively labeled version of the substance being tested.
The term is used primarily in scientific, medical, and research contexts to describe the assay procedure itself or to refer to its results.
- The doctor ordered a radioimmunoassay to check the patient's insulin levels.
- The development of the radioimmunoassay revolutionized endocrinology by allowing the measurement of previously undetectable hormones.
- The laboratory specializes in performing radioimmunoassays for various research projects.
- The technique is often abbreviated as RIA.
- It is considered a type of because the radioactive antigen and the non-radioactive antigen from the sample compete for a limited number of antibody binding sites.
- While extremely sensitive, its use has declined in some areas due to the need for radioactive materials, with methods like enzyme-linked immunosorbent assay (ELISA) often being preferred for routine testing.
- Immunoassay (n): A broader category of biochemical tests that measure the presence or concentration of a substance using an antibody. Radioimmunoassay is a specific type of immunoassay.
- Radioimmunoassayable (adj): Capable of being measured or analyzed by radioimmunoassay.
- Immunoradiometric assay (a related but technically different method)
- RIA (acronym)
The word is a compound formed from: * Radio-: Pertaining to radiation or radioactivity. * Immuno-: Pertaining to the immune system or immune reactions. * Assay: A procedure for analyzing or testing a substance.
It literally means an "assay using radioactive labels and immune reactions."
-
immunoassay of a substance that has been radioactively labeled
