Cortisol
cortisol test · stress hormone test · serum cortisol
This is a blood test from a vein. It shows your level of cortisol, a hormone made by the adrenal glands.
For possible adrenal problems, sudden changes in weight or blood pressure, or strong weakness.
⏱ Duration: the blood draw takes a few minutes; results usually come in 1 to 3 days
Be sure to tell your doctor
How to prepare
- Time. Cortisol changes during the day. Blood is usually taken in the morning, at the time your doctor sets.
- Food. Usually fasting: no food for 8 to 12 hours. Plain water is fine. Check with the lab.
- The day before. No alcohol, no hard workouts, and no smoking. Try to get a good night's sleep.
- Medicines. Do not stop them on your own. Tell your doctor what you take. They will decide if anything should change.
What to bring
- Your test request form
- Your ID
How it goes
- Before the draw, sit quietly for 15 to 30 minutes, if the lab asks you to
- You sit down and rest your arm on the armrest
- A band is tightened above your elbow
- The skin is wiped with antiseptic
- A quick prick, and blood fills a tube
- The needle comes out, and a cotton pad is pressed on the spot
What you'll feel
- A quick prick, like a pinch
- Sometimes slight dizziness. Tell the nurse
Afterwards
- Press the cotton pad for 3 to 5 minutes and keep your arm straight
- You can eat right away and go back to your usual day
- Results usually come in 1 to 3 days. The lab will tell you when
- Sometimes the doctor also orders a saliva or urine cortisol test
Common questions
Why does the time of the test matter?
Cortisol is higher in the morning and lower in the evening. Your doctor compares your result with the normal range for that time.
Will stress affect the result?
Yes, stress raises cortisol. That is why you are asked to rest before the draw.