The 24-hour urinary aldosterone excretion test measures the amount of aldosterone removed in the urine in a day.
Aldosterone can also be measured with a blood test.
A 24-hour urine sample is needed. You will need to collect your urine over 24 hours. Your health care provider will tell you how to do this. Follow instructions exactly.
Your provider may ask you to stop taking certain medicines a few days before the test so that they don't affect the test results. Be sure to tell your provider about all the medicines you take. These include:
Do not stop taking any medicine before talking to your doctor.
Be aware that other factors can affect aldosterone measurements, including:
Do not drink coffee, tea, or cola during the day the urine is collected. Your provider will likely recommend that you eat no more than 3 grams of salt (sodium) per day for at least 2 weeks before the test.
The test involves only normal urination. There is no discomfort.
The test is done to see how much aldosterone is released into your urine. Aldosterone is a hormone released by the adrenal gland that helps the kidney control salt, water, and potassium balance.
Results depend on:
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
A higher than normal level of aldosterone may be due to:
Lower than normal levels may indicate Addison disease, a disorder in which the adrenal glands do not produce enough hormones.
There are no risks with this test.
Reviewed By: Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.