Test Quick Guide

Cortisol testing measures the level of cortisol, a hormone produced by the adrenal glands. Cortisol helps regulate metabolism, blood pressure, immune function and the body’s response to stress. Testing is used to evaluate whether cortisol levels are too high or too low and to help diagnose disorders affecting the adrenal or pituitary glands.

Cortisol levels change naturally throughout the day in a predictable pattern. Levels are typically highest in the early morning and lowest late at night. Because of this daily rhythm, cortisol tests are often collected at specific times to provide accurate results. Some tests require samples at multiple times of day to assess normal cortisol patterns.

Cortisol levels can fluctuate due to stress, illness, exercise and medications. For this reason, a single cortisol measurement may not always provide a complete picture of adrenal function. In some situations, additional testing such as ACTH stimulation or dexamethasone suppression may be needed to confirm a diagnosis.

About Our Cortisol Test

Purpose of the test

Cortisol testing is used to assess adrenal gland function and help diagnose hormone disorders.

  • Screening for cortisol imbalance: Testing helps determine whether cortisol levels are higher or lower than normal.
  • Diagnosing adrenal or pituitary conditions: Results can help identify disorders such as Cushing syndrome or adrenal insufficiency.
  • Monitoring treatment: Cortisol tests may be used to evaluate the effectiveness of treatment for adrenal gland disorders.

What does our cortisol test measure?

Cortisol testing measures the amount of cortisol in the blood, saliva or urine. Different tests are used depending on the suspected condition and the timing required.

  • Blood cortisol test: Measures cortisol in a blood sample, usually collected in the early morning between 7 a.m. and 9 a.m. when cortisol levels are highest.
  • Salivary cortisol test: Measures cortisol in saliva, often collected late at night when levels should be lowest. This test is frequently used to evaluate possible cortisol excess.
  • 24-Hour urine free cortisol test: Measures the total amount of cortisol released in urine over a full day. This test helps assess overall cortisol production and is commonly used to screen for Cushing syndrome.
  • ACTH stimulation test: Evaluates how the adrenal glands respond to adrenocorticotropic hormone (ACTH) and is used to help diagnose adrenal insufficiency.
  • Dexamethasone suppression test: Assesses whether cortisol production can be suppressed by a steroid medication. This test is used to help diagnose conditions that cause high cortisol levels.

In many cases, providers use more than one type of cortisol test to accurately evaluate adrenal function because cortisol values can vary widely based on time of day and individual circumstances.

When should I get a cortisol test?

A cortisol test may be recommended if you have symptoms that suggest abnormal cortisol levels.

Testing for high cortisol may be appropriate if you experience:

  • Unexplained weight gain, especially around the abdomen or face
  • High blood pressure
  • Easy bruising or thinning skin
  • Muscle weakness
  • Elevated blood sugar
  • Irregular menstrual periods

Testing for low cortisol may be recommended if you experience:

  • Extreme fatigue
  • Low blood pressure
  • Unexplained weight loss
  • Dizziness or fainting
  • Abdominal pain
  • Nausea or vomiting
  • Darkening of the skin

Common causes of high cortisol levels include long-term use of corticosteroid medications, pituitary or adrenal tumors, severe stress and certain metabolic disorders.

Common causes of low cortisol levels include adrenal insufficiency, pituitary gland disorders and sudden withdrawal from prolonged steroid therapy.

Your doctor may also order cortisol testing if you have a known pituitary or adrenal condition, or if other laboratory tests suggest a hormone imbalance.

Finding a Cortisol Test

How to get tested

Cortisol testing is typically ordered by a doctor and performed in a hospital, laboratory or medical clinic. Depending on the type of test, a blood sample, saliva sample or 24-hour urine collection may be required.

For blood testing, a sample is drawn from a vein and sent to a laboratory for analysis. Saliva and urine tests are often completed at home using laboratory-provided collection kits.

Can I take the test at home?

Certain cortisol tests, including salivary cortisol and 24-hour urine cortisol tests, can be completed at home. These tests require collecting samples at specific times and returning them to a laboratory for processing.

At-home tests can provide helpful information about cortisol patterns, but abnormal results often require follow-up testing ordered by a healthcare provider to confirm a diagnosis.

How much does the test cost?

The cost of cortisol testing depends on the specific test performed, where it is completed and whether you have health insurance. Blood cortisol tests are often covered by insurance when ordered by a doctor, though copays and deductibles may apply.

If you do not have insurance, a doctor or laboratory can help explain available testing options and expected costs.

Taking a Cortisol Test

Cortisol testing may be performed using a blood sample, saliva sample or urine collection.

Before the test

Preparation depends on the type of cortisol test. For many blood tests, your doctor will recommend that the sample be collected in the early morning. You may be asked to avoid intense exercise, alcohol or certain medications before testing. For salivary tests, you may be instructed not to eat, drink or brush your teeth shortly before collecting the sample.

Always tell your doctor about any prescription or over-the-counter medications you are taking, as some drugs can affect cortisol levels.

During the test

For a blood cortisol test, the process generally involves:

  • Locating a vein in the arm or hand
  • Cleaning the puncture site
  • Inserting a small needle and collecting blood

The procedure usually takes only a few minutes. Mild discomfort or bruising may occur.

Saliva tests involve collecting a small sample at a designated time of day. Urine tests require collecting all urine produced over a 24-hour period according to detailed instructions.

After the test

There are no restrictions on normal activities after sample collection. Your healthcare provider will inform you when to expect results.

FAQs About a Cortisol Test

Why does the time of day matter for cortisol testing?

Cortisol follows a natural daily rhythm, rising in the morning and falling at night. Because of this pattern, many cortisol tests must be collected at specific times to be meaningful. Testing at the wrong time can lead to misleading results.

How and when will I receive my test results?

Results are usually available within a few business days. If your test was ordered by a doctor, you will typically receive results through a follow-up visit, patient portal, phone call or secure email. At-home test results are provided by the testing company after the laboratory processes the sample.

What does an abnormal cortisol test mean?

An abnormal result may indicate that cortisol levels are too high or too low. High cortisol can be associated with Cushing syndrome or prolonged steroid use, while low cortisol may suggest adrenal insufficiency or pituitary problems. Additional testing is often needed to confirm the cause.

What happens if my cortisol levels are abnormal?

If results are abnormal, your healthcare provider may recommend further evaluation such as ACTH stimulation testing, dexamethasone suppression testing or imaging studies. Treatment depends on the underlying cause and may involve medication or referral to an endocrinologist.

Can stress affect my cortisol test results?

Yes. Emotional stress, physical illness, intense exercise and certain medications can temporarily raise cortisol levels. Your provider will consider these factors when interpreting results and may recommend repeat testing if needed.

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