Cortisol, Free (Serum)
This test measures the amount of free cortisol, a form of the hormone cortisol that circulates freely in your blood. Free cortisol is important for regulating stress responses, metabolism, and other bodily functions.
["Free cortisol helps your body manage stress and maintain balance in your hormones and metabolism."]
Key facts at a glance
- LOINC
- 93481-0
- Short code
- Cortis 10M p 1 ug/kg CRH IV SerPl-mCnc
- Synonyms
- Cortis 10M p 1 ug/kg CRH IV 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
- CPT
- 86701
- 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 Might Be Ordered
Your healthcare provider may order a free cortisol test to check for conditions like Cushing’s syndrome (too much cortisol) or Addison’s disease (too little cortisol). It can also help diagnose adrenal gland issues, hormone imbalances, or evaluate responses to stress or medications.
No special preparation is needed, but you may be asked to avoid certain medications or supplements that could affect results. If you’re taking steroids or other hormones, let your provider know.
A blood sample will be taken from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The sample is then sent to a lab for analysis.
Free cortisol levels can vary based on your time of day, stress levels, and overall health. Your provider will interpret the results in relation to your symptoms and medical history.
High cortisol levels might suggest conditions like Cushing’s syndrome, while low levels could indicate adrenal insufficiency or other hormonal disorders. Your provider will discuss these findings with you.
Free cortisol is often checked in people with suspected adrenal gland disorders, pituitary problems, or those experiencing unexplained weight changes, fatigue, or mood swings.
Your provider may also use this test to monitor treatment for conditions affecting cortisol production or balance.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Free cortisol helps assess whether your body is producing enough cortisol to manage stress, sleep, and metabolism effectively. Abnormal levels may indicate underlying health concerns that need medical attention.
Short name
Free Cortisol
Frequently asked questions
What causes abnormal cortisol levels?
How often should I get this test?
Can diet or stress affect 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