24-hour urinary aldosterone excretion test

24-Hour Urinary Aldosterone Excretion Test

The 24-hour urinary aldosterone excretion test is a diagnostic test used to measure the amount of the hormone aldosterone that is excreted in the urine over a 24-hour period. It is used to detect and diagnose the cause of a rare hormone-related disorder known as primary aldosteronism, in which the adrenal glands produce excessive amounts of the hormone aldosterone.


Before the test, the patient is instructed not to consume any foods or drinks that contain caffeine. In addition, the patient should be on medications containing a steroid, such as prednisone, for at least four weeks before the test.


During the procedure, the patient will be asked to collect a 24-hour urine sample in a special container. The urine sample needs to be collected in multiple containers, as each container will be tested for different components. The sample will then be sent to a lab for analysis.


There are different types of 24-hour urinary aldosterone excretion tests. These include the traditional 24-hour urinary aldosterone excretion test, the 24-hour urine collection with a gamma interferon stimulation test, the diurnal rhythm test, the spot urinary aldosterone/plasma renin activity ratio test, and the fludrocortisone suppression test.


The 24-hour urinary aldosterone excretion test has no major risks associated with it. Minor complications, such as discomfort or pain at the collection site, may occur during the test.

Why the Test is Performed

The 24-hour urinary aldosterone excretion test is performed to diagnose primary aldosteronism, which is caused by an overproduction of aldosterone by the adrenal glands. It is also used to monitor the effectiveness of treatment for this condition.

When the Test is Performed

The 24-hour urinary aldosterone excretion test should be performed when the patient’s symptoms suggest possible primary aldosteronism. These symptoms include high blood pressure, headaches, and fatigue.