In adults with hypertension and a positive screening test for primary aldosteronism, referral to a hypertension specialist or endocrinologist is recommended for further evaluation and treatment. Synopsis Primary aldosteronism is defined as a group of disorders in which aldosterone production is inappropriately high for sodium status, is relatively autonomous of the major regula- tors of secretion (angiotensin II and potassium), and cannot be suppressed with sodium loading.S5.4.2-2,S5.4.2-3 The increased production of aldosterone induces hypertension; cardiovascu- lar and kidney damage; sodium retention; suppressed plasma renin activity; and increased potassium excretion, which, if prolonged and severe, may cause hypokalemia. However, hypokalemia is absent in the majority of cases and has a low negative predictive value for the diagnosis of primary In about 50% of the patients, primary aldosteronism is due to increased unilateral aldosterone pro- duction (usually aldosterone-producing adenoma or, rarely, unilateral adrenal hyperplasia); in the remaining 50%, pri- mary aldosteronism is due to bilateral adrenal hyperplasia Whelton et al 2017 High Blood Pressure Clinical Practice Guideline e33 Recommendation-Specific Supportive Text 1. Primary aldosteronism is one of the most frequent dis- orders (occurring in 5% to 10% of patients with hyper- tension and 20% of patients with resistant hyperten- sion) that causes secondary hypertension.S5.4.2-5,S5.4.2-6 The toxic tissue effects of aldosterone induce greater target organ damage in primary aldosteronism than in primary hypertension. 