Cortisol, Free, 24-Hour Urine
This test measures the amount of free cortisol, a form of the hormone cortisol, that you excrete in your urine over 24 hours. It helps assess how well your body produces and regulates cortisol, which plays a key role in managing stress, metabolism, and other bodily functions.
["This test helps diagnose conditions related to cortisol imbalance, such as Cushing’s syndrome or adrenal insufficiency."]
Key facts at a glance
- LOINC
- 25621-4
- Short code
- Cortis sp3 p chal SerPl-sCnc
- Synonyms
- Cortis sp3 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 Is This Test Done?
Your doctor may order this test if they suspect an issue with your adrenal glands or pituitary gland, which control cortisol production. It can also be used to monitor treatment for conditions like Cushing’s syndrome or adrenal disorders. Sometimes, it’s part of a broader evaluation for unexplained weight changes, fatigue, or other symptoms linked to hormone imbalances.
What Does the Test Involve?
You’ll collect urine samples throughout the day and night in a special container. Typically, you’ll start right after waking up and continue until you’ve collected about 24 hours’ worth. The samples are then sent to a lab for analysis.
What to Expect Before the Test
No special preparation is usually needed, but you may be advised to avoid certain medications or supplements that could affect cortisol levels. Your doctor might also ask you to keep a stress diary or note any changes in your routine to help interpret the results accurately.
What to Expect During the Test
The test involves simple urine collection—just empty your bladder into the container at regular intervals. You’ll likely be given clear instructions on how to do this properly to ensure accurate results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
High cortisol levels in urine can indicate conditions like Cushing’s syndrome, where the body produces too much cortisol, often due to a tumor or other disorder. Low cortisol levels may suggest adrenal insufficiency, where the adrenal glands don’t produce enough cortisol to meet your body’s needs. This test helps doctors diagnose these conditions and guide treatment plans, such as medication adjustments or further testing.
Short name
Free Cortisol Urine Test
Frequently asked questions
What does a high or low result mean?
How often will I need this test?
Can I take medications before or after 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