Renal vein renin in essential hypertension.

A frequency distribution curve and interval percentages of variations in right versus left renal vein renin (RVR) were calculated from 227 sets of renin data from patients with mild and moderate essential hypertension (EH). A renal vein renin ratio (RVRR), large/small, of approximately 2.0 or more falls beyond the 95 per cent confidence interval, and may therefore by considered to be abnormal. Although assay variability and sampling errors may contribute to artifactually large RVRR's in EH, they usually indicate true disparity, probably secondary to asymmetrical nephrosclerosis. Recent hypotheses regarding diagnostic value of RVR in hypertension are evaluated in light of data yielded by this investigation. Simultaneous and/or replicate sampling should reduced within-patient variability and improve clinical interpretation of test results.