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Medical Term:


Pronunciation: rā′dē-ō-im′yū-nō-as′sā

Definition: An immunologic (immunochemical) procedure that uses competitive inhibition between a radioisotope-labeled antigen or other substance and unlabeled antigen for antiserums, binding as a means to quantify the agent of interest; any method for detecting or quantitating antigens or antibodies using radiolabeled reactants. Minute quantities of enzymes, hormones, or other substances can be assayed.