Understanding Your Laboratory Test: What It Is, How It Is Performed, and How to Get Ready for Your Appointment

This test is a laboratory evaluation that helps your healthcare provider check how your body is working, look for signs of illness, and monitor a condition you may already have. Your doctor will use the results, together with your symptoms and medical history, to guide decisions about your care.

The 16-beta,18-dihydroxydehydroepiandrosterone test measures the amount of a specific metabolite of dehydroepiandrosterone (DHEA) in your urine. DHEA is a hormone produced by the adrenal glands that serves as a precursor to other important hormones like estrogen and testosterone. This 24-hour urine test helps doctors understand how your body processes and eliminates this hormone.

The test is performed by a trained member of the medical staff. Depending on what your doctor has ordered, a small sample of blood may be drawn from a vein in your arm, or a urine, saliva, or swab sample may be collected. The procedure usually takes only a few minutes, and most people can return to their normal activities right afterward.

For this test, you will collect all urine produced over a 24-hour period. You will be given a special container for collection. On the first day, you will start collecting urine after your first morning void and continue collecting for the next 24 hours, including the first morning urine on the second day. During collection, keep the container refrigerated or in a cool place. Label the container with your name, date, and collection times. Return the complete collection to the laboratory as instructed.

To prepare for the test, follow any instructions your healthcare provider gave you. You may be asked to fast, meaning no food or drink except water, for 8 to 12 hours before your appointment, or to avoid certain medications and supplements. Drink water unless told otherwise, tell the staff about all medicines you take, and wear a sleeve that can easily be rolled up if a blood sample is expected.

Before the test, inform your doctor about all medications you are taking, as certain drugs can affect the results. You may need to stop taking some medications, especially hormonal treatments, corticosteroids, or supplements containing DHEA. Follow your doctor's instructions regarding any dietary restrictions. Avoid strenuous exercise before and during the collection period, as it can affect hormone levels. Your doctor will provide specific instructions based on your medical situation.