Renin–aldosterone testing: The essentials

Primary aldosteronism (PA) is a common yet significantly underdiagnosed cause of secondary hypertension, estimated to affect around 9.4% of hypertensive adults. This is critical because patients with PA face markedly higher rates of adverse cardiovascular and renal outcomes, risks substantially mitigated by targeted treatment (surgery or medical therapy). Despite this, screening rates remain critically low. This article provides a practical, evidence-based approach to PA screening specifically for generalist settings, focusing on contemporary test interpretation and mitigating common pitfalls. Screening involves a simple blood test for plasma aldosterone and renin. The diagnostic hallmark is renin-independent aldosterone production, demonstrated by suppressed renin. While most antihypertensives interfere, the initial approach is to test patients on their current regimen. If results are inconclusive, medication withdrawal is warranted. Specialist referral is necessary when results are suggestive of PA, or in complex cases like chronic kidney disease. Improving PA screening offers a significant opportunity for substantial global benefit in reducing hypertension-related morbidity and mortality.