Single oral administration of captopril may not bring an improvement in screening of primary aldosteronism.

Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured in 19 cases with primary aldosteronism (PA) and 72 with essential hypertension (EHT) to differentiate the two disorders in the following conditions: after overnight recumbency (basal state) and after oral administration of captopril. Screening criteria were determined in order to pick up all of PA patients as positive. After the captopril administration, the specificity of a criterion based on the combination of PAC and PAC/PRA ratio was 93% and positive predictive value 79%. This criterion was superior to other conventional screening methods. However, higher specificity (97%) and positive predictive value (90%) were obtained from a combination criterion based on the basal PAC and PAC/PRA ratio. The single oral administration of captopril may not bring an improvement in the screening of PA.