Table 6.1-1. Differential diagnosis of different causes of hypoaldosteronism

Etiology

Plasma renin activity

Serum aldosterone

Serum cortisol

Hyporeninemic hypoaldosteronism

Normal

Primary adrenal insufficiency

­↑

Adrenal enzyme deficiency

­↑

Normal or ↓

­↑, increased; ↓, decreased.