Aldosterone:Renin Ratio

The Aldosterone-to-Renin Ratio is a blood test that compares two hormones involved in controlling your blood pressure: aldosterone, made by your adrenal glands, and renin, made by your kidneys. When aldosterone is too high compared to renin, it may mean one or both adrenal glands are producing too much aldosterone on their own—a condition called primary aldosteronism that can cause high blood pressure and low potassium. This test is often used when blood pressure is difficult to control or when certain patterns in routine labs suggest a hormonal cause. Certain medications and dietary habits can affect the results, so your doctor will give you specific instructions before the test. A single abnormal result does not confirm a diagnosis; additional testing is usually needed.

When elevated: An elevated ARR suggests autonomous aldosterone secretion relative to renin suppression, raising concern for primary aldosteronism. This finding is associated with increased cardiovascular risk, including hypertension, hypokalemia, left ventricular hypertrophy, and increased risk of stroke and atrial fibrillation beyond that explained by blood pressure alone. Confirmatory testing (e.g., salt loading, fludrocortisone suppression) and adrenal imaging are typically indicated. When low: A low ARR generally indicates that aldosterone secretion is appropriately regulated by renin, or that renin is elevated relative to aldosterone. This pattern may be seen in secondary hyperaldosteronism, renovascular hypertension, renin-secreting tumors, or physiological states such as volume depletion and sodium restriction. A low ARR effectively reduces the likelihood of primary aldosteronism as a cause of hypertension.

The ARR is not typically relevant to routine athlete monitoring. However, it may become clinically important if an athlete develops unexplained hypertension or experiences unusual electrolyte imbalances (sodium/potassium) affecting performance or recovery. Primary aldosteronism is rare and usually detected through clinical evaluation rather than screening in healthy individuals.