Cortisol, Salivary, Free, 24-Hour Composite

This test measures the amount of cortisol, a hormone made by your adrenal glands that helps your body respond to stress, regulate blood sugar, control blood pressure, and support your immune system. Your doctor may order this test to look for conditions such as Cushing syndrome, when the body makes too much cortisol, or Addison disease, when it makes too little, as well as problems with the pituitary gland.

Your healthcare provider may order this test if they suspect conditions like Cushing’s syndrome (too much cortisol) or Addison’s disease (too little cortisol). It can also help diagnose other hormonal imbalances or evaluate how your body responds to stress. Sometimes, it’s used to monitor treatment effectiveness for conditions affecting cortisol levels.

Cortisol levels naturally rise and fall during the day, so your doctor may ask you to come in at a specific time, often in the early morning. You may be told to avoid eating or drinking anything except water for a period of time, skip strenuous exercise the day before, or temporarily stop certain medicines such as steroid drugs or birth control pills. Never stop taking any prescribed medicine without first talking to your doctor, and let your care team know if you are pregnant or have been under unusual stress.

No special preparation is needed. You’ll collect saliva samples throughout the day, typically in a special collection kit provided by your lab. You may be asked to avoid certain foods or medications that could affect cortisol levels, such as caffeine or some supplements, but this depends on your specific instructions from your provider.

The most common version of this test is a simple blood draw from a vein in your arm. A trained technician will clean the site, place a thin needle into the vein, and collect a small tube of blood, which usually takes only a few minutes. You may feel a quick pinch or sting, and the area may be slightly sore afterward. Depending on what your doctor orders, cortisol can also be measured with a saliva sample or a 24-hour urine collection instead of or in addition to a blood test.

You’ll use a saliva collection device to gather small amounts of saliva at regular intervals over 24 hours. The samples are usually collected in a kit that includes multiple tubes. After collection, the samples are sent to a lab for analysis.

Because cortisol levels change throughout the day, your doctor will read your numbers based on when your sample was taken, along with your symptoms and medical history. Higher-than-expected levels may point to conditions such as Cushing syndrome, ongoing stress, or the effect of certain medicines, while lower-than-expected levels may suggest adrenal insufficiency or a pituitary problem. Your doctor will explain what your specific results mean and whether any follow-up testing or treatment is needed.

Results are compared to reference ranges specific to cortisol levels in saliva. Abnormally high or low levels may indicate hormonal imbalances or other health issues. Your healthcare provider will interpret the results in the context of your medical history and symptoms.