Cortisol (Serum) – 24-Hour Urinary Free Cortisol
This test measures the amount of cortisol, a natural steroid hormone, excreted in your urine over a full day. It helps assess how well your body produces and regulates cortisol, which plays a key role in managing stress, immune response, and metabolism.
["This test helps diagnose conditions related to cortisol imbalance, such as Cushing’s syndrome or adrenal insufficiency."]
Key facts at a glance
- LOINC
- 1418-3
- Short code
- Cortis 30M p 250 ug ACTH IM SerPl-mCnc
- Synonyms
- Cortis 30M p 250 ug ACTH IM SerPl-mCnc
- Category
- hormone
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 60
- 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 This Test Is Done
Your doctor may recommend this test if they suspect an issue with your adrenal glands, pituitary gland, or if you have symptoms like unexplained weight changes, fatigue, or unusual mood swings. It’s also used to monitor conditions like Cushing’s syndrome or to check for cortisol overproduction or deficiency.
How the Test Works
You’ll collect all your urine for a full 24-hour period, typically starting and ending at the same time each day. The sample is then sent to a lab for analysis to measure cortisol levels in your urine.
What to Expect Before the Test
No special preparation is needed, but you may be asked to avoid certain medications that could affect results. Drink plenty of water to help your body naturally excrete cortisol.
What to Expect During the Test
You’ll collect your urine in a container over the course of a day. Some labs may provide a 24-hour urine collection kit with instructions to ensure accuracy.
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.
High cortisol levels in urine may indicate Cushing’s syndrome, where the body produces too much cortisol due to a tumor or other cause. Low cortisol levels could signal adrenal insufficiency, where the adrenal glands don’t produce enough cortisol. This test helps doctors diagnose and monitor these conditions by providing a comprehensive picture of cortisol metabolism over time.
Short name
24-Hour Urine Cortisol
Frequently asked questions
How long does it take to get the results?
Can I take any medications before the test?
What if I miss any urine during the collection period?
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