Screening for primary aldosteronism

Abstract
A serum potassium determination is usually recommended for new hypertensive patients as a screening test for primary aldosteronism and as a baseline for drug therapy. Since hypokalemia is not specific for aldosteronism, the authors assessed its use and limitations as a screening test in nine reported studies of 303 patients with aldosterone-producing adenomas (n=252) or adrenal hyperplasia (n=51). The optimal potassium cutoff level and the predictive ability of hypokalemia to detect aldosteronism were analyzed in a primary care setting with different diseases, test characteristics, and prevalences. Optimal screening for primary aldosteronism occurred at serum potassium <3.2 mEq/l in a primary care, low-prevalence population, and at higher potassium levels in higher-prevalence populations. Other screening tests, such as urinary aldoster-one levels and plasma renin activity, showed lower individual test performance characteristics, but when combined were similar in performance to serum potassium measurement.