DefinitionAn aldosterone test measures the amount of the hormone aldosterone in blood.
How the test is performedA blood sample is needed. For information on how this is done, see: Venipuncture
How to prepare for the testYour doctor may tell you how much salt you can eat before the test.
How the test will feelWhen the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performedThis test is performed for:Certain fluid and electrolyte disordersHard to control blood pressureLow blood pressure upon standing (orthostatic hypotension)Aldosterone is a hormone released by the adrenal glands. It helps the body regulate blood pressure.Aldosterone increases the reabsorption of sodium and water and the release of potassium in the kidneys. This action raises blood pressure.Often, blood aldosterone levels are combined with other tests to diagnose over- or under-production of the hormone. These tests may include:ACTH infusion testCaptopril testIntravenous saline infusion testPlasma renin activityRenin - aldosterone ratio
Normal ValuesNormal levels vary:Between children, teens, and adultsDepending on whether you were standing, sitting, or lying down when the blood was drawnNormal values vary from lab to lab. Talk to your doctor about your specific test results.
What abnormal results meanHigher than normal levels of aldosterone may indicate:Bartter syndrome (extremely rare)Primary hyperaldosteronismSecondary hyperaldosteronism from heart or kidney diseaseVery low-sodium diet Lower than normal levels of aldosterone may indicate:Addison's diseaseCongenital adrenal hyperplasiaHyporeninemic hypoaldosteronismVery high-sodium diet
What the risks areVeins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.Other risks associated with having blood drawn are slight but may include:Excessive bleedingFainting or feeling lightheadedHematoma (blood accumulating under the skin)Infection (a slight risk any time the skin is broken)
Special considerationsFactors that can affect aldosterone measurements include:Amount of salt in the dietStrenuous exerciseStressMany medications can influence aldosterone levels, including:ACE inhibitorsCalcium channel blockersDiureticsHeparinLithiumNonsteroidal anti-inflammatory drugs (NSAIDs)Propranolol
ReferencesNieman LK. Adrenal cortex. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, PA: Saunders Elsevier; 2007:chap 245.Young WF Jr. Endocrine hypertension. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 16.