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. Patients with primary aldo- steronism have a 3.7-fold increase in HF, a 4.2-fold increase in stroke, a 6.5-fold increase in MI, a 12.1- fold increase in atrial fibrillation (AF), increased left ventricular hypertrophy (LVH) and diastolic dysfunc- tion, increased stiffness of large arteries, widespread tissue fibrosis, increased remodeling of resistance vessels, and increased kidney damage as compared with patients with primary hypertension matched for Because the deleterious effects of aldosterone overproduction are often reversible with unilateral laparoscopic adrenalectomy or treatment with mineralocorticoid receptor antagonists (ie, spi- ronolactone or eplerenone), screening of patients with hypertension at increased risk of primary aldosteron- ism is beneficial.S5.4.2-2,S5.4.2-3 These include hypertensive patients with adrenal incidentaloma, an incidentally discovered adrenal lesion on a computed tomography or magnetic resonance imaging (MRI) scan performed for other purposes. Patients with hypertension and a history of early onset hypertension and/or cerebro- vascular accident at a young age may have primary aldosteronism due to glucocorticoid-remediable al- dosteronism (familial hyperaldosteronism type-1) and therefore warrant screening.S5.4.2-2,S5.4.2-3 2. The aldosterone:renin activity ratio is currently the most accurate and reliable means of screening for primary Table 14. 