Development of radioimmunoassay kit for atrial natriuretic factor in plasma

A specific radioimmunoassay (RIA) kit for Atrial Natriuretic Factor (ANF) is developed and applied to the measurement of human plasma. ANF is iodinated according to the method of Ch-T and purified by sephadex G50. The specific activity of 125I-ANF is more than 10 MBq/μg, the radiochemical purity is more than 90% and the excessive antibody binding is (78-81)%. The kit has a set of stable lyophilization standards. The range of detection is from 65 pmol/L to 3250 pmol/L. The assay method is simple and quick with the following characteristics: the average recovery in human plasma is (93.4-115)%, the intra and inter coefficients of variation are (3.2-4.5)% and (3.1-6.2)%, respectively, the nonspecific binding is (1.9-4.4)%, the detection limit is 17 pmol/L and the correlation coefficient of high value plasma dilution is 0.9992-0.9998. The content of ANF in 97 healthy adults is 122.0 +- 24.8 pmol/L