radioimmunoassay

noun

1. 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.

noun

1. 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

n.

1. The immunoassay of a substance, such as a hormone or an enzyme that has been radiolabeled.

1. 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.