Cortisol measured over a 24-hour period by high-performance liquid chromatography (HPLC)

Why This Test Is Done

Your doctor may recommend a 24-hour urine cortisol test if they suspect conditions like Cushing’s syndrome (overactive adrenal glands producing too much cortisol) or adrenal insufficiency (underactive adrenal glands). It can also help rule out other causes of symptoms such as weight gain, fatigue, or high blood pressure.

What to Expect Before the Test

You’ll collect your urine in a special container for 24 hours, starting right after you wake up and ending just before you wake up the next day. Store the urine in a refrigerator or at room temperature, and keep the container clean. Avoid certain medications that can affect cortisol levels, as instructed by your doctor.

What the Test Results Mean

Higher-than-normal cortisol levels in urine may indicate conditions like Cushing’s syndrome. Lower-than-normal levels could suggest adrenal gland problems or other hormonal imbalances. Your doctor will interpret the results in relation to your symptoms and other tests.

Common Conditions This Test Helps Diagnose

This test is particularly useful for diagnosing hormonal imbalances linked to the adrenal glands or pituitary gland, such as Cushing’s disease, adrenal insufficiency, or ectopic ACTH syndrome.