A specific enzymeimmunoassay for progesterone in human plasma.

An enzymeimmunoassay for plasma progesterone was established using progesterone covalently linked to the enzyme, horseradish peroxidase, as the 'label'. Separation of free and bound steroid was effected by Sepharose-coupled antiprogesterone-11alpha-hemisuccinyl bovine serum albumin antiserum (Sepharose-antisera). The enzymeimmunoassay satisfied the normal criteria of specificity, precision and accuracy. Comparison of assay results obtained by radioimmunoassay (with and without thin-layer chromatography) and enzyme-immunoassay (with and without thin-layer chromatography) showed excellent agreement of results in all cases (r greater than 0.98). This enzymeimmunoassay is particularly applicable to the routine determination of plasma progesterone in the smaller clinical laboratory.