Cortisol, 24-Hour Urinary Free Cortisol
This test measures the amount of cortisol, a natural steroid hormone, excreted in your urine over a 24-hour period. It helps assess your body’s cortisol production and can help diagnose conditions related to adrenal gland function.
["This test helps check if your adrenal glands are producing enough cortisol, often used to evaluate adrenal insufficiency or hyperfunction."]
Key facts at a glance
- LOINC
- 26526-4
- Short code
- Cortis F 48h p ACTH 24h Ur-mCnc
- Synonyms
- Cortis F 48h p ACTH 24h Ur-mCnc
- Category
- hormone
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Ref low
- 10
- Ref high
- 60
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your doctor may order this test if they suspect conditions like Cushing’s syndrome (overactive adrenal glands producing too much cortisol) or Addison’s disease (underactive adrenal glands). It can also be used to monitor treatment responses for these conditions or other hormonal imbalances.
How the Test Works
You’ll collect all urine for a full 24-hour period, typically starting after you urinate in the morning. The sample is then sent to a lab for analysis to measure cortisol levels in your urine.
Sample Collection Instructions
To prepare, empty your bladder at the start of the test (morning urine). Collect every urine sample in a container for the next 24 hours, including overnight. Store samples refrigerated if not tested immediately. Avoid certain medications (e.g., birth control pills, steroids) that may affect results.
What to Expect During Testing
You’ll likely need to wear a collection device (like a special container) around your waist or use a urine collection kit provided by your healthcare team. Most people can do this at home, but your doctor may guide you. Avoid alcohol, caffeine, or certain medications before testing.
Reference range
NCBI: ACTH 10-60 pg/mLN/A
Typically collected in the morning (8-10 AM). Inform your provider if taking steroid medications.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated cortisol levels may indicate Cushing’s syndrome, while lower levels could suggest adrenal insufficiency or other hormonal disorders. Abnormal results help guide treatment, such as medication adjustments or further testing for underlying causes like tumors or pituitary issues.
Short name
24-Hour Urine Cortisol
Frequently asked questions
What causes abnormal cortisol levels?
How long does it take to get results?
Can I eat or drink anything before the 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 17, 2026. · Read our editorial policy