radioimmunoassay (redirected from radioimmunoassays)

radioimmunoassay /ra·dio·im·mu·no·as·say/ (-im?u-no-as´a) a highly sensitive and specific assay method that uses the competition between radiolabeled and unlabeled substances in an antigen-antibody reaction to determine the concentration of the unlabeled substance, which may be an antibody or a substance against which specific antibodies can be produced.

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ra·di·o·im·mu·no·as·say (rd--my-n-s, --my-)

n. Abbr. RIA

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

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radioimmunoassay

a sensitive assay method used for the measurement of minute quantities of specific antibodies or any antigen, such as hormones or drugs, against which specific antibodies can be raised; abbreviated RIA. An assay for a specific hormone uses antihormone antibody produced by injecting the human hormone into an animal, such as a rabbit. In the assay either the antigen or antibody is labeled with radioisotope.