[A simple diagnostic test for primary hyperaldosteronism].

Plasma aldosterone levels were measured as part of two suppression tests in 31 hypertensive patients on normal sodium diet and without recent treatment. Thirteen patients had essential hypertension, 6 had probable bilateral adrenal hyperplasia and 12 had confirmed Conn's adenoma. In the first test, aldosterone levels were measured in the supine patients, then after infusion of 2 litres of isotonic saline over 2 hours. In the second test, aldosterone levels were measured before and 3 hours after oral administration of Captopril 1 mg/kg. Plasma aldosterone values superior to 360 pmol.l-1 after sodium load or to 665 pmol.l-1 after Captopril were characteristic of primary hyperaldosteronism due to adenoma. The test using Captopril has the advantages of being rapid, of avoiding acute blood volume expansion and of being applicable to all forms of hypertension, including severe ones.