The Aldosterone-to-Renin Ratio Test, also known as the ARR test, is a laboratory test used to diagnose and monitor conditions such as primary aldosteronism, Conn's syndrome, and aldosteronism. This test measures the levels of two hormones in the blood: aldosterone and renin. Aldosterone is a hormone produced by the adrenal glands that helps regulate sodium and potassium levels in the body. Renin is an enzyme produced by the kidneys that helps regulate blood pressure. The ratio of aldosterone to renin is normally around 20-40, but can be elevated in individuals with certain conditions.
The ARR test is often ordered to diagnose primary aldosteronism, a condition characterized by excessive production of aldosterone, which can lead to high blood pressure, low potassium levels, and other symptoms. The test is also used to monitor treatment for primary aldosteronism and to distinguish it from other conditions that may cause similar symptoms. The ARR test is usually performed as part of a comprehensive evaluation of patients with hypertension, particularly those who have not responded to conventional treatment.
The results of the ARR test are interpreted by comparing the patient's aldosterone-to-renin ratio to the normal range. An elevated ratio suggests that the patient has primary aldosteronism or another condition that affects the adrenal glands. A normal ratio indicates that the patient's aldosterone and renin levels are within normal ranges.