[ rey-dee-oh-im-yuh-noh-as-ey, -a-sey, -i-myoo- ]
/ ˌreɪ di oʊˌɪm yə noʊˈæs eɪ, -æˈseɪ, -ɪˌmyu- /


a test procedure that integrates immunologic and radiolabeling techniques to measure minute quantities of a substance, as a protein, hormone, or drug, in a given sample of body fluid or tissue.

Origin of radioimmunoassay

First recorded in 1960–65; radio- + immunoassay Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for radioimmunoassay


/ (ˈreɪdɪəʊˌɪmjʊnəʊˈæseɪ) /


a sensitive immunological assay, making use of antibodies and radioactive labelling, for the detection and quantification of biologically important substances, such as hormone concentrations in the blood
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for radioimmunoassay


[ rā′dē-ō-ĭm′yə-nō-ăsā, -ĭ-myōō′- ]


The immunoassay of a substance, such as a hormone or an enzyme that has been radiolabeled.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for radioimmunoassay


[ rā′dē-ō-ĭm′yə-nō-ăsā, -ĭm-yōō′- ]

An immunoassay in which the substance to be identified or quantified is labelled with a radioactive substance (called a tracer), such as an ion. See also immunoassay tracer.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.