Cortisol (Serum) 24-Hour Urinary Free Cortisol
This test measures how much cortisol your body releases over 24 hours through your urine. It helps assess your adrenal gland function and whether you have conditions like Cushing’s syndrome or adrenal insufficiency.
["This test helps diagnose hormonal imbalances related to cortisol production."]
Key facts at a glance
- LOINC
- 1450-6
- Short code
- Cortis pre 2 mg Dex high SerPl-mCnc
- Synonyms
- Cortis pre 2 mg Dex high SerPl-mCnc
- Category
- hormone
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 20
- Ref high
- 400
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82670
- 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 this test if they suspect conditions affecting your adrenal glands, such as Cushing’s syndrome (too much cortisol) or Addison’s disease (too little cortisol). It can also be used to monitor treatment for these conditions or other hormonal disorders.
How the Test Works
You’ll collect all your urine over a full day and return it to the lab. The test measures cortisol levels in your urine, which reflects how much cortisol your body naturally produces and releases.
Sample Collection
To prepare, empty your bladder before starting and collect every drop of urine for the next 24 hours. Store the sample in a clean container at room temperature until you return it to the lab on the same day.
What to Expect
You’ll likely need to wear a urine collection bag or use a container to collect all urine. Some patients may need to use a catheter for overnight collection. Follow your healthcare provider’s instructions carefully to ensure accurate results.
Reference range
Premenopausal: 20-400 pg/mL; Postmenopausal: <30 pg/mLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated cortisol levels may indicate Cushing’s syndrome, caused by excess cortisol from tumors or prolonged steroid use. Low cortisol levels could signal adrenal insufficiency, where the adrenal glands don’t produce enough hormones. This test helps diagnose and monitor these conditions, guiding treatment decisions.
Short name
24-Hour Urine Cortisol
Frequently asked questions
What does a high cortisol level mean?
What does a low 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