What happens during a cortisol test?A cortisol test is usually in the form of a blood test. During a blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.Because cortisol levels change throughout the day, the timing of a cortisol test is important. A cortisol blood test is usually done twice a day–once in the morning when cortisol levels are at their highest, and again around 4 p.m., when levels are much lower.Cortisol may also be measured in a urine or saliva test. For a cortisol urine test, your health care provider may ask you to collect all urine during a 24-hour period. This is called a "24-hour urine sample test." It is used because cortisol levels vary throughout the day. For this test, your health care provider or a laboratory professional will give you a container to collect your urine and instructions on how to collect and store your samples. A 24-hour urine sample test usually includes the following steps:Empty your bladder in the morning and flush that urine away. Record the time.For the next 24 hours, save all your urine passed in the container provided.Store your urine container in the refrigerator or a cooler with ice.Return the sample container to your health provider's office or the laboratory as instructed.A cortisol saliva test is usually done at home, late at night, when cortisol levels are lower. Your health care provider will recommend or provide you with a kit for this test. The kit will likely include a swab to collect your sample and a container to store it. Steps usually include the following:Do not eat, drink, or brush your teeth for 15-30 minutes before the test.Collect the sample between 11 p.m. and midnight, or as instructed by your provider.Put the swab into your mouth.Roll the swab in your mouth for about 2 minutes so it can get covered in saliva.Don't touch the tip of the swab with your fingers.Put the swab into the container within the kit and return it to your provider as instructed.
