The ratio of plasma aldosterone concentration to renin activity (ARR) is a sensitive parameter for screening of primary aldosteronism (PA) and for predicting prognosis after adrenalectomy in patients with PA.Study of the influencing factors for ARR,especially medications,sodium intake and posture,is of great significance for improving the screen efficacy of ARR.This paper introduces the current application of ARR in screening for PA and optimization of its determining conditions.

The ratio of plasma aldosterone concentration to plasma renin activity (ARR) is a practical parameter in screening for primary aldosteronism (PA).However,variations of the cutoff value of ARR in different studies have been reported due to plenty of influential factors that may affect the secretions of renin and aldosterone. Lack of standardization of assays for ARR also makes direct comparisons among different studies difficult.The associated influential factors on ARR were introduced in this review.

Objective Plasma renin concentration (PRC) offers advantages in processing and standardization as compared with plasma renin activity (PRA). The aim of the study is to compare the sensitivity and specificity of plasma aldosterone concentration ( PAC)/PRA (ARR) and PAC/PRC (AARR) in screening primary aldosteronism ( PA ) in hypertensive patients and to observe the influence of different postures on PRC and AARR. Method ( 1 ) PAC and PRC in the supine position and after 1-hour and 2-hour upright posture were determined in 28 patients with PA and 51 patients with essential hypertension. The diagnostic efficacies during different postures were compared according to the ROC curve analysis. (2) 31 patients with PA, 242 patients with essential hypertension, and 145 normotensitive subjects were recruited in the study. The diagnostic efficacy of AARR in screening PA from hypertensive patients was evaluate. PAC, PRA, and PRC were measured by radioimmunoassay. Results ( 1 ) The AUC of AARR in the supine position, 1-hour and 2-hour upright posture were0.950 (95% CI0.906-0.994, P<0. 01), 0.979 (95% CI0.956-1.000, P<0.01) and 0.917 (95% CI 0. 856-0. 979, P<0. 01 ) respectively. AARR of 1 -hour upright yielded the highest screening efficiency. ( 2 ) The correlation coefficient index of Log-PRA and Log-PRC was 0. 705 ( P< 0. 01, n = 418 ), whereas the correlation coefficient index of Log-ARR and Log-AARR was 0.705 (P<0.01, n=418). The AUC of ARR and AARR were 0.998 (95% CI0. 981-1. 000, P<0.01 ) and 0.957 (95% CI0. 929-0.985, P<0.01 ) respectively according to the ROC curve. The optimal cutoff of AARR during upright 1 hour was 42.36 ng · dl-1/ng ·dl-1 ( sensitivity 87.10%, specificity 93.75% ). Conclusion The screening efficacy of AARR in screening PA in hypertensive patients was comparable with ARR. AARR measured after keeping upright 1 hour yielded the highest screening efficiency. The optimal cutoff of AARR was 42.36 ng · dl-1/ng ·dl-1.