Cortisol, Free (Serum or Plasma)
This test measures the amount of free cortisol, a form of the hormone cortisol, in your blood. Free cortisol is the active, unbound portion that circulates freely in your bloodstream and is important for regulating stress responses and metabolism.
["Free cortisol helps your body manage stress and maintain balance in hormones and energy."]
Key facts at a glance
- LOINC
- 28550-2
- Short code
- Cortis Ur Ql
- Synonyms
- Cortis Ur Ql
- Category
- hormone
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why This Test Might Be Ordered
Your doctor may recommend this test if they suspect an issue with your adrenal glands, pituitary gland, or Cushing’s syndrome (a condition where your body produces too much cortisol). It could also be used to evaluate adrenal insufficiency (Addison’s disease) or to monitor treatment for conditions like Cushing’s syndrome.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for a few hours before the test if it involves a blood draw. If your doctor has specific instructions, follow them closely. Avoid taking any medications that might affect cortisol levels unless cleared by your doctor.
What Happens During the Test
A healthcare professional will draw blood from a vein in your arm. The blood sample will be sent to a lab for analysis. The test typically takes a few minutes, and you may feel slight discomfort or bruising at the site.
What the Results Mean
Results are interpreted by your doctor based on your medical history, symptoms, and other test results. Elevated levels may indicate conditions like Cushing’s syndrome, while low levels could suggest adrenal insufficiency or other hormonal imbalances.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Free Cortisol
Frequently asked questions
How does free cortisol differ from total cortisol?
Can stress affect my cortisol levels?
What are common conditions linked to abnormal cortisol levels?
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