Aldosterone
Aldosterone is the adrenal hormone that tells kidneys to keep sodium (and water) and dump potassium. Abnormal values explain otherwise unexplained hypertension or potassium imbalance.
What it measures
Aldosterone is produced by the adrenal cortex in response to the kidney's renin signal. It acts on the distal nephron to reabsorb sodium and water and to excrete potassium and hydrogen. Aldosterone is the final lever the body uses to defend blood pressure and circulating volume — too much causes hypertension with low potassium; too little causes salt-losing hypotension with high potassium. The aldosterone-to-renin ratio (ARR) is the screening test of choice for primary aldosteronism — a fixable cause of resistant hypertension that's commoner than once thought (5–10% of hypertensive adults).
What a high value can mean
- Primary aldosteronism (Conn's syndrome) — adrenal adenoma or bilateral hyperplasia; high aldosterone with suppressed renin.
- Secondary aldosteronism — heart failure, cirrhosis, nephrotic syndrome, renovascular hypertension; high aldosterone with high renin.
- Diuretic therapy / volume depletion — appropriate physiological response.
What a low value can mean
- Adrenal insufficiency (Addison's disease) — combined with low cortisol, low sodium, high potassium.
- Hyporeninemic hypoaldosteronism — diabetic kidney disease, NSAIDs.
- Congenital adrenal hyperplasia (some forms).
- ACE inhibitors / ARBs — therapeutic suppression of renin → aldosterone.
When to discuss with a doctor
Aldosterone is rarely an isolated outpatient test — it's usually paired with renin (the ARR) and interpreted against the patient's blood pressure, sodium and potassium. Resistant hypertension on three drugs, hypertension with spontaneous hypokalaemia, or an adrenal incidentaloma is the typical trigger. Mediora.AI surfaces the value with sodium/potassium so the pattern is visible; primary aldosteronism diagnosis requires confirmatory testing by an endocrinologist.