Cortisol, Serum (24-Hour Urinary Free Cortisol)
This test measures the amount of cortisol, a natural steroid hormone, that your body excretes in urine over a full day. It helps assess how well your adrenal glands are producing cortisol, which plays a key role in managing stress, immune response, and metabolism.
["This test helps diagnose adrenal gland disorders, including Cushing’s syndrome or Addison’s disease."]
Key facts at a glance
- LOINC
- 25623-0
- Short code
- Cortis sp5 p chal SerPl-sCnc
- Synonyms
- Cortis sp5 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 conditions like Cushing’s syndrome (overactive adrenal glands causing high cortisol levels) or Addison’s disease (underactive adrenal glands leading to low cortisol). It can also help evaluate stress responses or rule out other hormonal imbalances.
What to Expect Before the Test
You’ll need to collect all your urine for a full 24-hour period, starting and ending at the same time each day. Store the urine in a refrigerator or freezer until you bring it to the lab. Follow your doctor’s instructions carefully to ensure accurate results.
How the Test Works
The test measures cortisol levels in your urine, which reflects how much cortisol your body naturally releases throughout the day. Unlike blood tests, this method avoids fluctuations caused by stress or timing of blood draws.
Possible Results and Next Steps
Results may be compared to reference ranges for healthy individuals. High levels could indicate Cushing’s syndrome or other adrenal issues, while low levels may suggest Addison’s disease or other hormonal problems. Your doctor will discuss findings with you and may recommend further testing or treatment.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Cortisol is a hormone produced by the adrenal glands and plays a critical role in regulating metabolism, immune response, and stress reactions. Abnormal urinary cortisol levels can signal underlying adrenal disorders or other conditions affecting hormone production.
Short name
24-Hour Urinary Free Cortisol
Frequently asked questions
What does a high urinary cortisol level mean?
What does a low urinary cortisol level mean?
How often should I get 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