Lab test
What is a cortisol test, and what are normal cortisol levels?
A cortisol test measures the adrenal hormone that helps the body respond to stress, control blood sugar and reduce inflammation. It is used to look for conditions that cause too much or too little cortisol, such as Cushing syndrome or Addison disease. ARUP Laboratories lists 6.0 to 18.4 mcg/dL for blood drawn between 6 and 10 a.m.
What does the cortisol test measure?
Cortisol is made by the adrenal glands. It helps the body respond to stress, reduce inflammation and carry out other functions throughout the body. MedlinePlus
Why is the cortisol test ordered?
- To help diagnose or rule out Cushing syndrome (too much cortisol), Addison disease or secondary adrenal insufficiency (too little), and to monitor treatment. MedlinePlus
What are typical cortisol ranges?
ARUP Laboratories publishes serum cortisol by time of day. ARUP Laboratories
Reference ranges differ between laboratories and testing methods, and many also differ by age, sex, pregnancy or the phase of the menstrual cycle. The range printed on your own report is the one that applies to your result, and a clinician interprets it alongside your history.
| Time of draw | Reference interval |
|---|---|
| 6 a.m. to 10 a.m. | 6.0 to 18.4 mcg/dL |
| 4 p.m. to 8 p.m. | 2.7 to 10.5 mcg/dL |
What can affect cortisol results?
- Time of day: a blood test may need two appointments at different times on the same day. MedlinePlus
- Stress and exercise can raise cortisol, so you may need to rest before the test. MedlinePlus
- Depression, anxiety, alcohol use disorder, poorly controlled diabetes and obesity can raise cortisol without an adrenal or pituitary tumor. MedlinePlus
When should you talk to a clinician about a cortisol result?
- A cortisol test alone cannot diagnose the cause of an abnormal level; more tests usually follow, chosen by a clinician. MedlinePlus
DiscoverMedica explains what a test measures and what named sources publish. It does not interpret individual results; the clinician who ordered your test, or one you choose, does.
Where can you get a cortisol test?
A clinician can order it as part of routine or follow-up care. Some services also let you order lab tests yourself; check that a service’s panel includes this marker, which laboratory runs it, and who reviews the result with you.
- Function HealthAnnual membership for broad lab panels, drawn at Quest sites or at home.
- Quest HealthOrder individual lab tests from Quest Diagnostics online, without a doctor’s visit.
Cortisol Test: questions, answered
What is a normal cortisol level?
It depends on the time of day. ARUP Laboratories lists 6.0 to 18.4 mcg/dL for blood drawn between 6 and 10 a.m., and 2.7 to 10.5 mcg/dL between 4 and 8 p.m. Saliva and urine cortisol tests use different ranges, and other labs print their own.
Can stress raise a cortisol test?
Yes. MedlinePlus notes that stress and exercise can raise cortisol, so you may be asked to rest before the test. It also lists depression, anxiety, alcohol use disorder, poorly controlled diabetes and obesity as causes of higher cortisol unrelated to a tumor.
Why are two cortisol blood tests done in one day?
Cortisol normally runs higher in the morning and lower later in the day, which is why ARUP publishes separate morning and evening ranges. MedlinePlus says a blood test may need two appointments at different times on the same day. Follow the scheduling instructions exactly.
Sources
Last reviewed October 7, 2026. Every source above was checked on or before that date. Educational information only, not medical advice; it does not replace a conversation with a licensed clinician. DiscoverMedica does not employ clinicians.