Cortisol, Free, 24-Hour Urinary
This test measures the amount of free cortisol (a form of the hormone cortisol) excreted in your urine over a 24-hour period. It helps assess how well your body produces and regulates cortisol, which is important for managing stress, immune function, and metabolism.
["This test helps diagnose conditions related to cortisol imbalance, such as Cushing’s syndrome or Addison’s disease."]
Key facts at a glance
- LOINC
- 77934-8
- Short code
- Cortis 9.5h p chal SerPl-sCnc
- Synonyms
- Cortis 9.5h p chal SerPl-sCnc
- Category
- hormone
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your doctor may order a 24-hour urinary free cortisol test if they suspect you have an overactive or underactive adrenal gland, unusual weight changes, fatigue, or other symptoms linked to cortisol imbalance. It’s also used to confirm or rule out conditions like Cushing’s syndrome or adrenal insufficiency.
How the Test Works
You’ll collect your urine for 24 hours, starting right after you wake up and ending just before you wake up the next day. Each time you urinate, you’ll pour the urine into a special container provided by your healthcare team. The collected urine is then sent to a lab for analysis.
What to Expect During the Test
There are no special preparations needed beyond collecting urine over a full day. You may need to keep a log of your urine output to ensure accuracy. Avoid certain medications or supplements that could affect cortisol levels before the test.
Possible Results and Interpretation
Results are compared to reference ranges specific to your age, sex, and health status. High levels may suggest Cushing’s syndrome, while low levels could indicate adrenal insufficiency or other conditions. Your doctor will discuss the results in the context of your symptoms and medical history.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated urinary free cortisol levels may indicate Cushing’s syndrome, a condition caused by prolonged exposure to high cortisol levels, often due to a tumor or other causes. Low levels may suggest Addison’s disease (adrenal insufficiency), where the adrenal glands don’t produce enough cortisol, or other adrenal or pituitary disorders. This test is critical for diagnosing and managing these conditions to prevent complications like muscle weakness, fatigue, or severe illness.
Short name
Free Cortisol Urine Test
Frequently asked questions
How long does it take to get my test results?
What should I do if I miss any urine collections during the 24-hour period?
Can I take any medications before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy