A high aldosterone-to-renin ratio means aldosterone is inappropriately high relative to renin, often indicating primary hyperaldosteronism (autonomous adrenal aldosterone production). It can cause sodium and water retention, high blood pressure, low potassium and metabolic alkalosis. This finding prompts confirmatory suppression testing and further evaluation (imaging or adrenal vein sampling) because treatment may include mineralocorticoid antagonists or surgery.

ARR = plasma aldosterone concentration (PAC) ÷ plasma renin activity (PRA). Typically PAC is in ng/dL and PRA in ng/mL/hr, so ARR = PAC (ng/dL) / PRA (ng/mL/hr). If renin is measured as direct renin concentration (DRC, mU/L), use PAC (ng/dL) / DRC (mU/L). Common screening cutoffs are ARR >20–30 with PAC ≥10 ng/dL.

A high aldosterone-to-renin ratio (ARR) most commonly indicates primary hyperaldosteronism—typically an aldosterone‑producing adrenal adenoma (Conn’s syndrome) or bilateral adrenal hyperplasia. Less common causes include familial hyperaldosteronism or adrenal carcinoma. Many medications and conditions (beta‑blockers, mineralocorticoid receptor antagonists, potassium‑sparing diuretics, low potassium, pregnancy) can falsely alter ARR, so medication review and confirmatory testing are needed.

ARR is calculated as plasma aldosterone concentration (PAC, ng/dL) divided by plasma renin activity (PRA, ng/mL/hr). An ARR above roughly 20–30 (PAC/PRA) suggests primary hyperaldosteronism; many protocols use ARR ≥20 with PAC ≥15 ng/dL, while others prefer ≥30 for higher specificity. A positive screen needs confirmatory testing (e.g., saline suppression), and drugs/positioning can affect results.

A high aldosterone‑renin ratio suggests primary aldosteronism; confirm with repeat/confirmatory testing and adrenal imaging. Treatment includes mineralocorticoid receptor antagonists (spironolactone or eplerenone), potassium replacement, and blood‑pressure control. If a unilateral adrenal adenoma is present, laparoscopic adrenalectomy may be curative. Advise salt restriction, regular monitoring of potassium and renal function, and referral to an endocrinologist for individualized management.

High renin activity occurs in conditions causing reduced renal perfusion or salt wasting—renovascular hypertension/renal artery stenosis, juxtaglomerular (renin‑secreting) tumors, chronic kidney disease/renal ischemia, heart failure, cirrhosis with ascites, nephrotic syndrome, dehydration or diuretic use, Bartter and Gitelman syndromes, pregnancy, and malignant hypertension. They elevate renin by decreasing renal perfusion, causing volume depletion, or producing renal sodium wasting that stimulates the renin–angiotensin–aldosterone system.