Cortisol, serum/plasma, mass concentration (24-hour urinary free cortisol)
This test measures the amount of cortisol (a natural steroid hormone) that you excrete in your urine over 24 hours. It helps assess how well your body produces and regulates cortisol, which is important for managing stress, immune function, and other bodily processes.
["This test helps diagnose conditions related to abnormal cortisol levels, such as Cushing’s syndrome or adrenal insufficiency."]
Key facts at a glance
- LOINC
- 12559-1
- Short code
- Cortis sp4 p chal SerPl-mCnc
- Synonyms
- Cortis sp4 p chal 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 Is This Test Done?
Your doctor may recommend this test if they suspect you have conditions like Cushing’s syndrome (too much cortisol), adrenal gland issues, or other hormonal imbalances. It’s also used to monitor treatment for conditions affecting cortisol production.
What Does the Test Involve?
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. This method provides a more accurate picture of your cortisol levels over time compared to a single blood or saliva sample.
How Is the Test Performed?
You’ll be given clear instructions on when to start and stop collecting urine. Store the sample in a refrigerator or freezer until you return it to the lab. Do not miss any urine—collect everything, including the first and last samples.
What Are Common Causes of Abnormal Results?
High levels may suggest conditions like Cushing’s syndrome, steroid use, or certain tumors. Low levels could indicate adrenal insufficiency, pituitary issues, or other hormonal disorders. Stress, certain medications, or even diet can also affect results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Cortisol plays a key role in regulating metabolism, immune response, and stress reactions. Chronic overproduction (hypercortisolism) or underproduction (hypocortisolism) can lead to serious health problems, including weight changes, fatigue, high blood pressure, or weakened bones. This test helps identify these imbalances early for better management and treatment.
Short name
24-Hour Urinary Free Cortisol
Frequently asked questions
What does a high urinary cortisol level mean?
What does a low urinary cortisol level mean?
How often should I get 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