Cortisol, Free, Serum (24-Hour Urinary Excretion)
This test measures the amount of free cortisol naturally excreted in your urine over a 24-hour period. Free cortisol is the active form of the hormone cortisol, which helps regulate stress responses, metabolism, and other bodily functions.
["Assesses long-term cortisol levels to diagnose conditions like Cushing’s syndrome or adrenal insufficiency."]
Key facts at a glance
- LOINC
- 9613-1
- Short code
- Cortis 2h p 250 ug ACTH IM SerPl-mCnc
- Synonyms
- Cortis 2h 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 Matters
Your body produces cortisol in response to stress, but certain medical conditions can cause either too much (hypercortisolism) or too little (hypocortisolism) cortisol. Free cortisol in urine reflects your body’s steady-state cortisol levels over time, helping doctors identify chronic imbalances that daily blood tests might miss.
When You Might Need It
A 24-hour free cortisol urine test is often used when doctors suspect conditions like Cushing’s syndrome (too much cortisol), adrenal insufficiency (too little cortisol), or other hormonal imbalances that affect stress responses or metabolism. It’s also sometimes ordered after a blood cortisol test if results are unclear.
What to Expect Before the Test
You’ll collect all your urine for a full 24-hour period, starting right after you wake up and ending just before you wake up the next morning. Keep a record of the time each sample is collected. Drink plenty of fluids to help urine flow, but avoid caffeine or medications that may affect cortisol levels unless instructed otherwise.
What Happens During the Test
After collecting your urine samples, they’ll be sent to a lab for analysis. The test measures the total amount of free cortisol in your urine over the day. No special preparation is needed beyond following the collection instructions carefully.
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.
Free cortisol in urine provides a more accurate picture of your body’s cortisol production than blood tests alone, especially for conditions like Cushing’s syndrome or adrenal insufficiency. Elevated levels may indicate overproduction of cortisol (e.g., from tumors or prolonged stress), while low levels may suggest adrenal gland problems or other hormonal disorders. This test helps doctors diagnose and monitor these conditions for treatment planning.
Short name
Free Cortisol Urine Test
Frequently asked questions
How is the test different from a blood cortisol test?
What does it mean if my results are high?
Can I take medications before 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 17, 2026. · Read our editorial policy