Cortisol (Salivary) 24-Hour Average
This test measures the average level of cortisol in your saliva over a 24-hour period. Cortisol is a hormone produced by your adrenal glands that helps regulate stress responses, metabolism, and immune function.
["Understanding your natural cortisol levels can help identify stress-related imbalances or conditions like Cushing’s syndrome or adrenal insufficiency."]
Key facts at a glance
- LOINC
- 16673-6
- Short code
- Cortis 50M p chal SerPl-mCnc
- Synonyms
- Cortis 50M 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 This Test Is Done
Your doctor may recommend a 24-hour salivary cortisol test if they suspect an issue with your adrenal glands or pituitary gland. It helps distinguish between conditions like Cushing’s syndrome (too much cortisol) or adrenal insufficiency (too little cortisol). Unlike blood tests, saliva cortisol reflects natural hormone levels without interference from stress-related spikes.
How the Test Works
You’ll collect saliva samples throughout the day in a special container. Each sample is placed in a separate tube, and the lab analyzes the combined results to determine your average cortisol level over 24 hours.
What to Expect Before the Test
No special preparation is needed, but avoid caffeine and smoking for a few hours before collecting samples to get more accurate results. Stressful events or medications (like steroids) can affect cortisol levels, so discuss these with your doctor.
What the Results Mean
Results help doctors diagnose hormonal imbalances by comparing your average cortisol levels to expected ranges. Abnormally high or low levels may indicate conditions requiring further medical evaluation.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Salivary Cortisol
Frequently asked questions
Why might my doctor order this test?
How do I prepare for this test?
What if I miss a sample or have an irregular schedule?
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