Abstract: A fluorescence polarization immunoassay (FPIA) for detecting the presence of one or more amphetamine-class analytes in a test sample is provided. The immunoassay uses competition between the analyte and a fluorescently labeled tracer for the binding site on an antibody specific for phenethylamine derivatives. The concentration of amphetamine-class analyte in the sample determines the amount of tracer that binds to the antibody. The amount of tracer-antibody complex formed can be quantitatively measured and is inversely proportional to the quantity of analyte in the test sample. The invention relates to tracers, to immunogens used to elicit antibodies for use as assay reagents, and to assay kits incorporating these tracers and assay reagents.

Abstract: A method for diagnosing rheumatoid arthritis, which is characterized by enzyme-immunologically measuring the amount of collagenase inhibitor present in sera, plasmas or synovial fluids by way of a sandwich assay wherein two different monoclonal antibodies which specifically bind to different antigenic determinants of the collagenase inhibitor are used, and comparing the measured amount with that for normal subjects.