Plasma or Serum Cortisol Level (24-Hour Profile)
This test measures your cortisol levels over a 24-hour period to help diagnose conditions related to your adrenal glands, such as Cushing’s syndrome or adrenal insufficiency.
["A 24-hour cortisol test helps identify whether your cortisol levels are too high or too low over time."]
Key facts at a glance
- LOINC
- 11831-5
- Short code
- Fet Kidney Diam.hilum-cort Est from GA
- Synonyms
- Fet Kidney Diam.hilum-cort Est from GA
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- estimated-from-gestational-age
- 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 this test if you have symptoms like unexplained weight gain, fatigue, high blood pressure, or unusual mood changes that might suggest hormonal imbalances. It’s also used to evaluate conditions like Cushing’s syndrome (caused by excess cortisol) or Addison’s disease (adrenal insufficiency).
What to Expect Before the Test
You’ll collect urine samples every few hours for 24 consecutive hours. Wear a bracelet or tracker to remind you to collect samples at consistent times. Store samples in the refrigerator until you return them to the lab. Follow your doctor’s instructions carefully to ensure accurate results.
What Happens During the Test
No special preparation is needed beyond collecting urine samples at home. Your doctor will provide detailed instructions on timing and storage. The test measures cortisol concentration in your urine, which reflects your body’s cortisol production throughout the day.
What the Results Mean
Results will compare your cortisol levels to typical ranges for a healthy adult. Abnormally high or low levels may indicate hormonal disorders. Your doctor will discuss the results with you and may recommend further testing or treatments based on findings.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
24-Hour Cortisol Test
Frequently asked questions
What causes abnormal cortisol levels?
How often is this test repeated?
Can diet or medications 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