ABSTRACT
Immunoassays are a class of analytical methods based on the selective a⁄nity of an antibody for an analyte [1^3]. Biological antibodies are highly useful analytical reagents,which may be produced by innoculation of laboratory animalswith the analyte or with a derivative. The archetypal immunoassay, the radioimmunoassay or RIA, involves competition for a limited number of antibody binding sites between the analyte, present at unknown concentration in the sample, and a radiolabelled probe. Immunoassays are widely employed in clinical analysis in particular, but also in other ¢elds including environmental analysis and research.
