VALIDATION OF AN IMMUNORADIOMETRIC ASSAY TO MEASURE PLASMA-LEVELS OF ACTIVE RENIN

An immunoradiometric assay (IRMA) for active renin in human plasma was analytically and clinically validated. Analytical validation established 1) precision, 2) recovery, 3) linearity, 4) cross-reactivity, 5) sample stability, and 6) the validity and specificity of the I-125-labeled anti-renin monoclonal in the Diagnostics Pasteur immunoradiometric renin kit. Clinical validation included 1) establishing a normal reference range for renin, 2) comparing plasma renin activity (PRA) results to immunoreactive renin levels in subjects on Upjohn research protocols, and 3) comparing the renin responsiveness of sodium replete subjects to that of sodium deplete subjects prior to, during, and after infusion with Upjohn renin inhibitory peptide, ditekiren. This study was undertaken to demonstrate the research validity of an assay tool for the differentiation of enzymatically active renin from inactive renin or a form of prorenin.