Cortisol (Serum) – 24-Hour Urinary Free Cortisol
This test measures how much cortisol, a natural steroid hormone, is excreted in your urine over a full day. It helps assess your body’s cortisol production and may be used to diagnose conditions like Cushing’s syndrome or adrenal insufficiency.
["This test helps check if your body produces too much or too little cortisol over time."]
Key facts at a glance
- LOINC
- 1429-0
- Short code
- Cortis 50H p 2 mg Dex SerPl-mCnc
- Synonyms
- Cortis 50H p 2 mg Dex SerPl-mCnc
- 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 This Test Is Done
Your doctor may order this test if they suspect conditions affecting your adrenal glands, such as Cushing’s syndrome (overproduction of cortisol) or adrenal insufficiency (underproduction). It can also be used to monitor treatment for these conditions or evaluate symptoms like weight changes, fatigue, or mood swings that may relate to hormone imbalances.
How the Test Works
You’ll collect all your urine over a 24-hour period, typically starting and ending at the same time each day. The urine is then sent to a lab for analysis to measure cortisol levels. This method provides a more accurate picture of your daily hormone activity compared to single blood tests.
Sample Collection
To prepare, empty your bladder before starting the collection. Use a clean container (like a urine bottle) and record the time you begin. Collect every urine sample, including the first and last voids of the day. Store the urine in a cool place if not testing immediately. Bring all collected urine to your doctor’s office or lab on the same day.
What to Expect During the Test
No special preparation is needed beyond the 24-hour urine collection. If you’re taking medications that might affect cortisol levels, inform your healthcare provider before starting the collection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated cortisol levels in urine may indicate Cushing’s syndrome, caused by prolonged exposure to high cortisol from conditions like a pituitary tumor or steroid use. Low cortisol levels could suggest adrenal insufficiency, where the adrenal glands don’t produce enough hormones. This test helps diagnose and monitor these conditions, guiding treatment decisions like medication adjustments or further testing.
Short name
24-Hour Urine Cortisol
Frequently asked questions
How long does the 24-hour urine collection take?
Can I drink alcohol or take certain medications during the urine collection?
What if I miss a urine sample during the 24-hour 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 16, 2026. · Read our editorial policy