A procedure that measures minute amounts of a substance, such as a hormone or drug, by quantitating the binding, or the inhibition of binding, of a radiolabeled substance to an antibody.
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Sci-Tech Encyclopedia:
Radioimmunoassay
A general method employing the reaction of antigen with specific antibody, permitting measurement of the concentration of virtually any substance of biologic interest, often with unparalleled sensitivity. The basis of the method is summarized in the competing reactions shown in the illustration. The unknown concentration of the antigenic substance in a sample is obtained by comparing its inhibitory effect on the binding of radioactively labeled antigen to a limited amount of specific antibody with the inhibitory effect of known standards.
Competing reactions that form basis of radioimmunoassay; * indicates the labeled antigen, and † “in known standard solutions or unknown samples.”
A typical radioimmunoassay is performed by the simultaneous preparation of a series of standard and unknown mixtures in test tubes, each containing identical concentrations of labeled antigen and specific antibody. After an appropriate reaction time the antibody-bound (B) and free (F) fractions of the labeled antigen are separated by one of a variety of techniques. The B/F ratios in the standards are plotted as a function of the concentration of unlabeled antigen (standard curve), and the unknown concentration of antigen is determined by comparing the observed B/F ratio with the standard curve.
The radioimmunoassay principle has found wide application in the measurement of a large and diverse group of substances in a variety of problems of clinical and biological interest. It is therefore not unexpected that there are differences in the specific methods employed for the assay of a particular substance. The full potential of the method has yet to be exploited. It seems that virtually any substance of biologic interest can be measured, the method being modified according to the characteristics of the particular substance. See also Antibody; Antigen; Immunology.
RIA (Royal Irish Academy), a learned body dedicated by its charter to ‘the cultivation of Science, Polite Literature, and Antiquities’; it came into being in 1785 with James Caulfield, Lord Charlemont, as its first President. The RIA was the immediate successor to the Hibernian Antiquarian Society, 1779-83, itself arising from the work of a Select Committee of the RDS, set up in 1772. In the 19th cent. it became the focus for philological, archaeological, and architectural studies. The RIA library became a major centre for the preservation of the literary and historical remains of Gaelic society. It now contains the Book of the Dun Cow, Leabhar Breac, the Book of Lecan, and an original autograph copy of part of the Annals of the Four Masters, along with 1, 400 manuscripts of various kinds.
Sports Science and Medicine:
radioimmunoassay
A sensitive technique widely used to measure a range of biological substances, and to detect drugs such as peptide hormones and anabolic steroids during dope testing. The technique is based on the ability of an unlabelled form of the substance to inhibit competitively the binding of a radioactively labelled substance by specific antibodies. The concentration of the unknown sample is determined by comparing the degree of inhibition with that produced by a series of standards containing known amounts of the substance. The reliability of the test depends on the precise specification of the conditions under which the tests are made.
Columbia Encyclopedia:
radioimmunoassay
(RIA), highly sensitive laboratory technique used to measure minute amounts of substances including antigens, hormones, and drugs present in the body. The substance or antigen (a foreign substance in the body that causes antibody production) to be measured is injected into an animal, causing it to produce antibodies. Serum containing the antibodies is withdrawn and treated with a radioactive antigen and later with a nonradioactive antigen. Measurements of the amount of radioactivity are then used to determine the amount of antigen present. The technique was developed by Solomon Berson and Rosalyn Yalow. Yalow was awarded the 1977 Nobel Prize in Physiology or Medicine for her work.
Veterinary Dictionary:
radioimmunoassay
A sensitive assay method used for the measurement of minute quantities of specific antibodies or any antigen, such as hormones or drugs, against which specific antibodies can be raised; abbreviated RIA. An assay for a specific hormone uses antihormone antibody produced by injecting the human hormone into an animal, such as a rabbit. In the assay either the antigen or antibody is labeled with radioisotope.
Wikipedia:
radioimmunoassay
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
Initially, the radioactive antigen is bound to the antibodies. When "cold" (unlabeled, quest) antigen is added, the two compete for antibody binding sites - at higher concentrations of "cold" antigen, more of it binds to the antibody, displacing the radioactive variant. The bound antigens are separated from the unbound ones.
One method of separation used initially was the use of a second antibody directed against the first for precipitation and centrifugation. The use of charcoal suspension for precipitation was extended but replaced later by Drs. Werner and Acebedo at Columbia University for RIA of T3 and T4.[1] An ultramicro RIA for human TSH was published in BBRC (1975) by Drs. Acebedo, Hayek et al.[2] The free hormone stays in the supernatant, the radioactivity of which is measured and a binding curve is plotted.
The technique is both extremely sensitive and specific, but it requires special precautions (because radioactive substances are used), sophisticated apparatus, and is expensive. The technique has been largely replaced by the ELISA method where instead of a radioactive signal, the antigen-antibody reaction is measured by colorometric signals.
The RIA was developed by Rosalyn Yalow and Solomon Aaron Berson in the 1950s.[3] Rosalyn Sussman Yalow received the 1977 Nobel Prize in Medicine for the development of the RIA for insulin. The precise measurement of minute amounts of such a hormone was a key event in endocrinology.
References
- ^ Werner SC, Acebedo G, Radichevich I (1974). "Rapid radioimmunoassay for both T4 and T3 in the same sample of human serum". J. Clin. Endocrinol. Metab. 38 (3): 493-5. PMID 4815178.
- ^ Acebedo G, Hayek A, Klegerman M, Crolla L, Bermes E, Brooks M (1975). "A rapid ultramicro radioimmunoassay for human thyrotropin". Biochem. Biophys. Res. Commun. 65 (2): 449-56. PMID 1148002.
- ^ Yalow RS, Berson SA. Immunoassay of endogenous plasma insulin in man. J Clin Invest 1960;39:1157-75. PMID 13846364.
External links
- RADIOIMMUNOASSAY- DETAILED PROCEDURE
- MeSH Radioimmunoassay
- http://www.lib.mcg.edu/edu/esimmuno/ch4/radassay.htm
| Immunologic techniques and tests - diagnostic immunology | |
|---|---|
| Immunoprecipitation | Chromatin immunoprecipitation - Immunodiffusion (Ouchterlony double immuno diffusion, Radial immunodiffusion, Immunoelectrophoresis, Counterimmunoelectrophoresis) |
| Immunoassay | ELISA - Enzyme Multiplied Immunoassay Technique - RAST test - Radioimmunoassay - Immunofluorescence |
| Other | Nephelometry - Agglutination (Hemagglutination) - Complement fixation test - Immunohistochemistry |
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 | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| Sci-Tech Encyclopedia. McGraw-Hill Encyclopedia of Science and Technology. Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved. Read more |
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| Irish Literature Companion. The Concise Oxford Companion to Irish Literature. Copyright © 1996, 2000, 2003 by Oxford University Press. All rights reserved. Read more |
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| Sports Science and Medicine. The Oxford Dictionary of Sports Science & Medicine. Copyright © Michael Kent 1998, 2006, 2007. All rights reserved. Read more |
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| Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/ Read more |
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| Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved. Read more |
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| Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Radioimmunoassay". Read more |
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Mentioned In:
- RIA (abbreviation)
- Farr test
- immunoradiometry
- Immunochemistry (immunology)
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