The Simultaneous Measurement of Plasma-Aldosterone- and -Renin-Concentration Allows Rapid Classification of all Disorders of the Renin-Aldosterone System

OBJECTIVE: The determination of the plasma aldosterone (PAC) to the plasma renin concentration (PRC) ratio is an accepted screening tool for primary hyperaldosteronism (PHyperA). DESIGN: To assess the diagnostic significance of this ratio for other disorders of the renin-aldosterone-system (RAS), we examined 60 patients with different adrenal diseases, 32 patients with essential hypertension and 76 normotensive healthy volunteers. The aldosterone (pmol/L) and renin (mU/L) concentrations were measured in one plasma sample by an automated chemiluminescence assay (Nichols Advantage). RESULTS: Patients with PHyperA (n=31) had a PAC/PRC ratio between 105 and 2328 and could be distinguished without overlap from the essential hypertension group (ratio: range 2.7-49) and normal healthy volunteers (ratio: range 0.9-71). Fourteen patients with primary hypoaldosteronism showed low PAC/PRC ratios (range 0.21-0.98) and low PAC values (range: 42-100). Seven patients with secondary hypoaldosteronism had normal PAC/PRC ratios (range 2.8-23.2) and low PAC values (range: 42-116). Eight patients with secondary hyperaldosteronism had normal PAC/PRC ratios (range 7.8-67.9) and elevated PAC values (range: 803-2917). The graphic presentation of these data allowed the differentiation of all major disorders of the RAS. CONCLUSIONS: The measurement of PAC/PRC ratios using this automated system provides a sensitive and rapid screening method for PHyperA. Moreover, the measurement of both the PAC and the PAC/PRC ratio allows differentiation of other disorders of the RAS.