Aldosterone Blood Test (ALD)

The Aldosterone Blood Test measures the concentration of aldosterone, a steroid hormone produced by the adrenal glands. Aldosterone is a key regulator of sodium and potassium balance and, consequently, of blood volume and blood pressure. This test is typically requested when a clinician suspects primary aldosteronism (Conn's syndrome), a condition in which the adrenal glands produce too much aldosterone, leading to hypertension that is often resistant to standard treatment, alongside low potassium levels. It is also used to investigate unexplained hypokalaemia, adrenal incidentalomas, or to monitor patients with known adrenal disorders. The test involves a simple blood sample, usually collected in the morning after you have been upright for at least two hours, as aldosterone levels follow a natural daily rhythm and posture can affect results. Your doctor may also request a paired renin measurement to calculate the aldosterone-to-renin ratio (ARR), which improves diagnostic accuracy.

Hormone Marker
- Aldosterone

Why it matters
Identifying elevated aldosterone is crucial because it points to a specific, often treatable cause of high blood pressure. Unlike essential hypertension, primary aldosteronism carries a higher risk of cardiovascular, renal, and metabolic complications if left untreated. Confirming the diagnosis allows for targeted therapy, which may include mineralocorticoid receptor antagonists or, in some cases, surgery to remove an affected adrenal gland. This can lead to better blood pressure control, correction of potassium imbalance, and a reduction in long-term health risks. The Aldosterone Blood Test therefore provides essential information that can transform the management of resistant hypertension and related conditions.