radioimmunoassay


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Related to radioimmunoassay: ELISA

radioimmunoassay

 (RIA) [ra″de-o-im″u-no-as´a]
a sensitive assay method that can be used for the measurement of minute quantities of specific antibodies or any antigen, such as a hormone or drug, against which specific antibodies can be raised. An assay for a specific hormone uses antihormone antibody produced by injecting the human hormone into an animal, such as a rabbit, and hormone that has been labeled with a radioisotope. These are mixed with the assay specimen and the antigen (hormone) bound to antibody is separated from the unbound antigen by chromatography or other means. Because any hormone in the assay specimen competes with the radiolabeled hormone for antibody binding sites, the amount of hormone in the specimen is inversely proportional to the radioactivity of the bound fraction or directly proportional to the activity of the free fraction. This is the standard method for clinical laboratory measurements of hormones and is also used for therapeutic drug monitoring, drug abuse screening, and other laboratory tests.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

ra·di·o·im·mu·no·as·say (RIA),

(rā'dē-ō-im'yū-nō-as'sā),
An immunologic (immunochemical) procedure that uses competitive inhibition between a radioisotope-labeled antigen or other substance and unlabeled antigen for antiserums, binding as a means to quantify the agent of interest; any method for detecting or quantitating antigens or antibodies using radiolabeled reactants. Minute quantities of enzymes, hormones, or other substances can be assayed.
Farlex Partner Medical Dictionary © Farlex 2012

radioimmunoassay

(rā′dē-ō-ĭm′yə-nō-ăs′ā, -ĭm-yo͞o′-)
n. Abbr. RIA
A technique used to quantitate minute amounts of a substance, such as a hormone, in blood or another liquid. It involves the use of radioisotopes and of antibodies to the substance being investigated.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

radioimmunoassay

see RIA.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

ra·di·o·im·mu·no·as·say

(RIA) (rā'dē-ō-im'yū-nō-as'sā)
An immunologic (immunochemical) procedure that uses the competition between radioisotope-labeled antigen (hormone) or other substance and unlabeled antigen for antiserums, resulting in quantitation of the unlabeled antigen; any method for detecting or quantitating antigens or antibodies using radiolabeled reactants.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

radioimmunoassay

Any method of measuring the extent of linkage between ANTIGEN and ANTIBODY in which one or other of these is labelled with a radioactive substance (radionuclide). Measurement of radiation can be remarkably precise.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
References in periodicals archive ?
The European radioimmunoassay market contributed the largest share to the global market, and was valued at USD 121.5m in 2014.
Liao, "Serum hydrocortisone (Cortisol) values in normal and adrenopathic dogs as determined by radioimmunoassay," American Journal of Veterinary Research, vol.
The action of the pure anti-estrogen is manifested to the same extent with BPA, as demonstrated by immunocyto-chemistry (Figure 4B) and radioimmunoassay (Figure 4C).
Radioimmunoassay screening of dried blood spot materials for benzoylecgonine.
Kubacki insists that his firm has devised a special method of washing hair samples that removes any outside environmental contaminants, and notes that all positive test results are verified independently using chromatography/mass spectrometry as a backup to radioimmunoassay. He calls the Alabama study "specious" and says it has never been peer reviewed.
Radioimmunoassay procedures are generally employed in plasma assays, many of which have been developed in this laboratory (Sangalang and Freeman 1987, Freeman et al.
Continuous development of novel immunological technique such as radioimmunoassay anticipated to increase the demand for carcinoembryogenic antigen test during forecast period.
These several kinds of immunoassays are based on: chemiluminescence, enzyme immunoassay, enzyme-linked Fluorescence, immunofluorescence, multiplexed assays and radioimmunoassay. The global immunoassay analyzers market report estimates the market size (Revenue USD million - 2013 to 2020) and composition of this market and also forecasts growth trends (CAGR% - 2016 to 2020).
TT4 was measured using 50 [micro]l undiluted serum with a commercially available radioimmunoassay kit (Union Medical and Pharmaceutical Technology (Tianjin) Ltd., China).
Plasma testosterone concentrations were measured by radioimmunoassay every 2 weeks for the first month after a new implant placement and then monthly thereafter.
The assay is at least fifty times more sensitive than the gold standard, conventional radioimmunoassay (RIA).