Cortisol, Serum (Mass Concentration)
This test measures the amount of cortisol, a natural steroid hormone produced by your adrenal glands, in your blood serum. Cortisol helps regulate metabolism, immune response, and stress reactions.
["Cortisol levels can provide insight into your body’s stress response and adrenal gland function."]
Key facts at a glance
- LOINC
- 58821-0
- Short code
- Cortis sp23 SerPl-mCnc
- Synonyms
- Cortis sp23 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 order a serum cortisol test to diagnose or monitor conditions like Cushing’s syndrome (overactive adrenal glands), Addison’s disease (underactive adrenal glands), or to check for adrenal insufficiency. It can also help evaluate stress-related symptoms or evaluate treatment responses for hormone-related disorders.
What to Expect Before the Test
No special preparation is needed for this test. You may have a small needle inserted into a vein in your arm, and blood will be drawn into a tube. If you’re taking medications that affect cortisol levels (like steroids), let your healthcare provider know.
What the Results Mean
Cortisol levels fluctuate throughout the day, peaking in the morning and dropping at night. A single test may not always show abnormal results, so your doctor might recommend testing at different times or multiple times to get a clearer picture.
Possible Causes of Abnormal Results
High cortisol levels might suggest conditions like Cushing’s syndrome, excessive stress, or certain tumors. Low cortisol levels could indicate adrenal insufficiency, pituitary disorders, or long-term steroid use.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Cortisol plays a key role in managing your body’s response to stress, immune function, and metabolism. Abnormal levels can signal underlying health issues that require medical attention. Your doctor will interpret results in the context of your symptoms and overall health.
Short name
Serum Cortisol
Frequently asked questions
Why might my cortisol levels be checked at different times of day?
What if I’m taking steroids or other medications that affect cortisol?
Can stress affect my cortisol test results?
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