24-Hour Urinary Free Cortisol Test

Why This Test Is Done

Your doctor may order this test if they suspect conditions like Cushing’s syndrome (excess cortisol), adrenal insufficiency, or other hormonal disorders that affect cortisol levels. It helps rule out whether your symptoms—such as weight changes, fatigue, or mood swings—are linked to abnormal cortisol production.

What to Expect Before the Test

You’ll collect all your urine for a full 24-hour period (typically from one morning to the next). Drink plenty of fluids to ensure adequate urine production. Avoid certain medications (like some antidepressants or steroids) that could affect cortisol levels unless your doctor instructs otherwise.

What Happens During the Test

You’ll provide a single urine sample at the end of the 24-hour period. The sample is sent to a lab for analysis using a sensitive immunoassay method to measure cortisol concentration.

What the Results Mean

Results are compared to a reference range for age/gender, though exact values aren’t provided here. Elevated levels may indicate overproduction of cortisol, while low levels could suggest adrenal gland dysfunction. Your doctor will interpret results in the context of your symptoms and medical history.