What does the Aldosterone test measure?

Why is Aldosterone measured?

Aldosterone measurement is central to diagnosing disorders of the renin-angiotensin-aldosterone axis. Autonomous overproduction (primary aldosteronism) is the most common curable cause of hypertension and must be distinguished from appropriate secondary aldosteronism driven by renal or renovascular disease. Aldosterone is never interpreted in isolation — the aldosterone-to-renin ratio (ARR) is the screening test, followed by confirmatory suppression studies. Low aldosterone with low renin suggests hyporeninaemic hypoaldosteronism (type 4 renal tubular acidosis), while low aldosterone with high renin points to primary adrenal insufficiency or aldosterone synthase defects.

Reference ranges

Standard reference

Upright (2 h standing): approximately 3–35 ng/dL; supine (morning): approximately 1–16 ng/dL. Position-dependent and assay-specific.

Functional medicine optimal

Optimal aldosterone is context-dependent: in a patient with hypertension and suppressed renin, a screening aldosterone above 10–15 ng/dL warrants confirmatory testing for PA; in hypotension and salt-wasting, undetectable or inappropriately low aldosterone suggests adrenal insufficiency or hypoaldosteronism.

Units

ng/dL, pmol/L

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.