24-Hour Urinary Free Cortisol (Mass Concentration)
This test measures the amount of cortisol naturally produced by your body over a 24-hour period, collected in your urine. It helps assess whether your adrenal glands are functioning properly to regulate stress hormones.
["A 24-hour cortisol test checks if your adrenal glands are making enough cortisol to handle stress."]
Key facts at a glance
- LOINC
- 1444-9
- Short code
- Cortis pre 12h fast SerPl-mCnc
- Synonyms
- Cortis pre 12h fast SerPl-mCnc
- Category
- hormone
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84484
- SNOMED
- 302774002
- 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 like Cushing’s syndrome (overproduction of cortisol) or adrenal insufficiency (underproduction). It’s also used to evaluate responses to stress or certain medications that affect cortisol levels.
How the Test Works
You’ll collect all your urine over 24 hours, typically starting after a morning void. The sample is sent to a lab for analysis to measure cortisol levels in your urine. This provides a full picture of your cortisol production over a full day.
What to Expect Before the Test
No special preparation is needed, but you should drink enough fluids to produce urine throughout the day. Avoid taking any medications that might affect cortisol levels (like some steroids) unless approved by your doctor.
What to Expect During the Test
You’ll collect your urine in a container every time you urinate, including first thing in the morning. The sample must be kept refrigerated and returned to the lab within 24 hours. Missing any urine or improper storage can affect results.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
24h Urinary Free Cortisol
Frequently asked questions
How long will I need to collect urine for this test?
Can I take medications before this test?
What if I miss a urine sample or don’t produce enough urine?
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