24-Hour Urinary Free Cortisol

Why This Test Is Done

Your doctor may recommend this test if they suspect an overproduction (hypersecretion) or underproduction (hyposecretion) of cortisol. Common reasons include unexplained weight changes, fatigue, high blood pressure, or symptoms of stress that don’t improve with usual treatments. It’s also used to monitor conditions like Cushing’s syndrome or adrenal gland disorders.

How the Test Works

You’ll collect all urine for a full 24 hours, typically starting after waking up and ending just before you wake up the next morning. The sample is then analyzed to measure cortisol levels in your urine. This method provides a more accurate picture of your cortisol levels over a full day compared to single-point measurements.

Sample Collection Process

To prepare, empty your bladder before starting the collection. Use a clean container (like a urine bottle) and keep it refrigerated if possible. Change the container every 6–8 hours to avoid contamination. Label the container with your name, date, and time. Bring all collected urine to the lab on the same day or refrigerate it until you can deliver it.

What to Expect After the Test

After collection, your sample will be sent to a lab for analysis. You’ll typically receive results within a few days. Your doctor will review the results with you to discuss any findings and next steps, such as further testing or treatment adjustments.