A very sensitive, specific laboratory test (assay) that uses radiolabeled and unlabeled substances in an immunological (antibody-antigen) reaction.

A technique to determine the concentration of a substance in a blood or tissue sample. A mixture of the substance to be measured and a form of the substance that has been radioactively tagged are allo [..]

A technique that uses antibodies to measure the concentration of a substance, such as a hormone, in blood. See Box 5.1.

Radioimmunoassay (RIA) is a heterogeneous competitive binding immunoassay in which the tracer material is a radioactive isotope.

(n) immunoassay of a substance that has been radioactively labeled

A radioimmunoassay was a pregnancy test developed in the 1970s that used a radioactive receptor site containing hCG antibodies to assess a woman’s pregnancy status.

Classic quantitative assay for detection of Antigen-Antibody Reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled subst [..]

Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled subst [..]

A method of protein analysis whereby it is possible to identify protein molecules surviving in fossils which are thousands and even millions of years old.

An assay that utilizes radiolabeled antigens or antibodies to quantitate antibody-antigen interactions.

A method to measure the amount of a substance using an antibody against the substance for specificity and a radioactive label for detection and measurement.

a procedure for assaying or quantifying minute amounts of target substances such as hormones, neurotransmitters, or drugs in blood or other tissue fluid. It is based on the action of the target substa [..]