Plasma renin activity in healthy subjects and patients with hypertension. Preliminary experience with a rapid and quantitative bio-assay

Abstract

RECENT observations have demonstrated that measurements of plasma renin activity (PRA) can contribute importantly to the evaluation of patients with hypertension.^1-9This procedure appears particularly useful to the evaluation of patients whose hypertension is secondary to either renovascular disease or primary aldosteronism. Plasma renin activity has been said to be elevated in patients with renovascular hypertension,^2-6,9and "suppressed" or low in patients with hypertension due to primary aldosteronism.^7,8,10In fact, Conn and his colleagues have suggested that the finding of reduced or "suppressed" PRA provides strong evidence for underlying primary aldosteronism even in the presence of normokalemia^8,10and that the incidence of primary aldosteronism may be as high as 20% among patients with "benign essential" hypertension.⁷ Despite its apparent usefulness and potential importance, the bio-assay of PRA has not yet enjoyed widespread use because of the complexity or qualitative nature of most existing methods.¹⁹¹¹¹⁵There is a real need for