Primary aldosteronism, a major form of low renin hypertension: from screening to diagnosis.

There is general consensus on the use of (but not cut-off values for) the aldosterone/plasma renin activity ratio as a screening test for primary aldosteronism. There is also agreement on the need for subsequent confirmatory testing, but not on the protocols to be chosen. The four most common confirmatory tests in clinical practice are oral sodium loading, intravenous saline infusion, captopril challenge and fludrocortisone administration plus sodium loading. The choice of test reflects multiple variables: patient factors (including accessibility, compliance and safety), established practice and cost. Finally, subtype forms and lateralization of aldosterone production should be established by bilateral adrenal venous sampling, despite its technical difficulty and varying criteria for success.