Term: immunoradiometric assay https://doi.org/10.1351/goldbook.I02983 Definition: An assay based on the reversible and non-covalent binding of an antigen by a specific antibody labelled with a radioactive nuclide as a tracer. Related Terms: 1) assay (http://doi.org/10.1351/goldbook.A00470). 2) antigen (http://doi.org/10.1351/goldbook.A00394). 3) antibody labelled (http://doi.org/10.1351/goldbook.A00384). 4) radioactive nuclide (http://doi.org/10.1351/goldbook.R05077). 5) tracer (http://doi.org/10.1351/goldbook.T06422). Source: PAC, 1994, 66, 2513. 'Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)' on page 2520 (https://doi.org/10.1351/pac199466122513) Citation: 'immunoradiometric assay' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.I02983 License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.