Who should take a diurnal cortisol test?

A medical professional will order a diurnal cortisol test if they need more information about your endocrine system.

Nearly anyone can take a diurnal cortisol test. Saliva and urine cortisol tests are noninvasive and have no known risks. Blood cortisol tests are minimally invasive and have some very minor risks and side effects, such as mild pain and bruising where the blood is drawn.

Do you have to prepare for a diurnal cortisol test?
Your healthcare professional will give you instructions to help you prepare for a diurnal cortisol test. For accurate results, follow their instructions carefully.

It’s important to try to relax on the day of the test, as stress can raise your cortisol levels. In addition, some diurnal cortisol tests require you to avoid physical activity for one day before the test.

You might also need to avoid certain medications or skin care products, particularly those that contain steroids. But it’s important to check with your doctor first.

Finally, if you are testing saliva, you should avoid eating, drinking, and brushing your teeth for at least half an hour before the test.