Cortisol, Serum (24-Hour Urinary Free Cortisol)

This test is done to give your healthcare provider important information about how your body is working. It can help detect a health condition early, confirm a diagnosis, or monitor a condition you already have so your treatment plan stays on track.

Your doctor may order this test if they suspect conditions like Cushing’s syndrome (too much cortisol) or adrenal insufficiency (too little cortisol). It can also be used to evaluate stress responses or rule out hormonal imbalances. Sometimes, it’s part of a broader evaluation for unexplained weight changes, fatigue, or other symptoms linked to hormone dysfunction.

The test measures specific substances in your body to show how well certain organs and systems are functioning. Your provider compares your results with established reference ranges to determine whether everything appears normal or whether further evaluation may be needed.

You’ll collect a 24-hour urine sample by collecting all urine produced in a day, typically in a special container. The sample is then sent to a lab for analysis to measure cortisol levels. Unlike blood tests, this method captures cortisol’s natural daily fluctuations.

A trained member of our care team will collect your sample using a quick, routine procedure. The collection usually takes only a few minutes, and the sample is then sent to a certified laboratory, where it is carefully analyzed and the results are shared with your provider.

No fasting is required for this test, as it measures cortisol in urine over a full day. However, follow any specific instructions your lab provides to ensure accurate results.

Before your test, your healthcare provider will explain the purpose of the procedure and give you any specific instructions, such as which medications to take or avoid. Arrive a few minutes early so we can verify your information, answer your questions, and help you feel comfortable before we begin.

No special preparation is usually needed, but avoid taking certain medications (like some steroids) that could affect cortisol levels without discussing it with your doctor. Stay hydrated but follow any specific instructions your lab provides.