24-Hour Urinary Free Cortisol
This test measures how much cortisol your body excretes in urine over a 24-hour period. Cortisol is a hormone produced by your adrenal glands that helps regulate metabolism, immune response, and stress.
["Assesses cortisol levels over a full day to check for adrenal gland function or stress-related hormone imbalances."]
Key facts at a glance
- LOINC
- 16667-8
- Short code
- Cortis F 48h Ur-mRate
- Synonyms
- Cortis F 48h Ur-mRate
- Category
- hormone
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- 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 Matters
Cortisol is a key hormone that responds to stress, but measuring it over 24 hours gives a clearer picture than a single blood test. This test helps doctors diagnose conditions like Cushing’s syndrome (too much cortisol) or adrenal insufficiency (too little).
How It Works
You’ll collect all your urine over a 24-hour period (starting and ending at the same time each day) and send it to the lab. The lab analyzes the urine to measure cortisol levels, which are then compared to expected ranges for your age and health status.
What to Expect
You’ll receive instructions on how to properly collect your urine sample. It’s important to follow these carefully to ensure accurate results. You may need to wear a special collection bag or use a container provided by your healthcare team.
Possible Causes
Abnormally high or low cortisol levels can be caused by stress, certain medications, thyroid disorders, or conditions affecting your adrenal glands. This test helps identify whether your hormone levels are functioning as they should.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
24h Urine Free Cortisol
Frequently asked questions
This test is often used to diagnose conditions like Cushing’s syndrome (caused by too much cortisol) or adrenal insufficiency (caused by too little cortisol). It can also help evaluate stress-related hormone imbalances or rule out other conditions affecting cortisol production.
You may experience mild discomfort from wearing a urine collection bag, but it’s temporary. If you have any questions about the collection process, ask your healthcare provider for guidance.
Your results will be reviewed by a healthcare provider who will compare them to your individual reference ranges. They may recommend additional tests or treatments based on the findings.
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