Cortisol, Serum, Free (24-Hour Urinary)
This test measures the amount of free cortisol your body excretes in urine over a full day. Free cortisol is the active form of the hormone that helps regulate stress responses and metabolism.
["Assesses your body’s cortisol production under normal daily conditions to help diagnose conditions like Cushing’s syndrome or adrenal insufficiency."]
Key facts at a glance
- LOINC
- 77931-4
- Short code
- Cortis 6h p chal SerPl-sCnc
- Synonyms
- Cortis 6h p chal SerPl-sCnc
- 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 Matters for Your Health
Cortisol is a hormone produced by your adrenal glands that plays a key role in managing stress, immune response, and metabolism. Measuring free cortisol in urine helps doctors determine if your body is producing too much or too little, which can affect your energy, mood, and overall health.
When You Might Need This Test
Your doctor may recommend this test if you have symptoms like unexplained weight changes, high blood pressure, fatigue, or signs of hormonal imbalances. It’s also used to monitor conditions like Cushing’s syndrome or adrenal disorders.
What to Expect Before the Test
You’ll need to collect all urine for a full 24-hour period, typically starting after midnight on one day and ending just before midnight the next. Store the urine in a refrigerator or freezer to keep it fresh until you return it to the lab.
What Happens During the Test
No special preparation is needed beyond collecting your urine sample. The lab will analyze the urine for free cortisol levels, which are compared to standard reference ranges to assess your hormone balance.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
High cortisol levels in urine may indicate conditions like Cushing’s syndrome, where the body produces too much cortisol due to overactive adrenal glands or pituitary tumors. Low cortisol levels could suggest adrenal insufficiency, where the adrenal glands don’t produce enough cortisol to meet your body’s needs. These imbalances can lead to serious health issues if untreated.
Short name
Free Cortisol Urine Test (24-hour)
Frequently asked questions
How long does it take to get results from this test?
What does a high or low cortisol level mean?
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 16, 2026. · Read our editorial policy