Cortisol is the body's primary stress hormone, crucial in the "flight or fight" response. It helps the body respond to physical, emotional, or environmental stress. It is also involved in metabolism, the immune response, and stress management.
This article will describe cortisol testing, including when testing is needed, how testing is conducted, and how to interpret test results.
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What is Cortisol?
Cortisol is a steroid hormone produced by the adrenal glands, which are located on top of the kidneys. It plays a crucial role in metabolism, the process by which the body converts food into energy. It also helps regulate blood sugar levels, ensuring cells have the energy to function properly.
Cortisol levels also affect blood pressure and the body's ability to respond to stress. Additionally, cortisol plays a key role in the body's immune response. Cortisol is also involved in managing stress; it helps the body mobilize resources to deal with the stressor. Once the stressful situation has passed, cortisol levels return to normal, allowing the body to recover and restore balance.
Maintaining balanced cortisol levels is essential for maintaining homeostasis, the body's state of balance. Over time, high cortisol levels change the body's ability to respond to stress, impairing its ability to fight infection.
What Is a Cortisol Test?
A cortisol test is a way to measure the hormone via blood, urine, saliva, or hair.
The levels of this hormone naturally change throughout the day depending on the body's needs. The body functions in a circadian rhythm, a 24-hour clock that guides sleep and wakefulness. Cortisol is naturally higher in the morning to help the body wake up and increase energy. Levels decrease throughout the day and are their lowest at night to help promote sleep.
The Purpose of a Cortisol Test
A medical provider might order cortisol testing to diagnose suspected adrenal gland disorders, Cushing's syndrome, or Addison's disease.
Adrenal gland disorders often involve a dysregulated HPA axis. The HPA axis is the feedback loop between the hypothalamus, pituitary gland, and adrenal glands. These organs work together to ensure the body responds appropriately to stress. When there is an imbalance, increased fatigue and feelings of burnout can result.
Cushing's disease occurs when the adrenal glands consistently release too much cortisol due to a tumor. Conversely, Cushing's syndrome occurs from long-term use of corticosteroid medications (typically used for respiratory and autoimmune diseases).
Symptoms may include a round ("moon") face, fat deposits on the upper back ("buffalo hump"), depression, weight gain, weakness, and bruising.
Addison's disease is an autoimmune condition that occurs when the adrenals cannot produce enough cortisol. Symptoms often include abdominal pain, low blood pressure, mood changes, darkening of the skin, and fatigue. Cortisol testing can assist in diagnosing these conditions.
Symptoms that suggest a possible adrenal disorder often prompt a provider to order cortisol testing. These may include:
- Fatigue
- Weight changes (loss or gain)
- Depression
- Anxiety
- Weakness
- Skin changes
Types of Cortisol Tests
Blood
Blood (serum) cortisol testing may be used to diagnose Cushing's syndrome or Addison's disease. Because of the body's circadian rhythm, cortisol levels are typically higher in the morning.
A healthcare provider may perform multiple cortisol blood tests to measure levels throughout the day. Blood testing is accurate, but collection may cause stress (fear of needles), which can change the results.
Saliva
Cortisol testing through saliva is easy and painless and may be used to test at home. Because saliva is an easy way to collect a sample, this method is a good option if the patient needs to measure their cortisol throughout the day.
Samples are often collected in the morning, at lunchtime, dinner, and before sleep. The main advantage of saliva testing is its convenience. Saliva testing is best for diagnosing HPA axis imbalances.
Urine
Urine cortisol testing allows the provider to see how well the body breaks down the hormone. There are several urine cortisol test options; some also measure other hormones to allow for better diagnosis. The advantages of urine testing are its convenience and ability to give a good overview of the HPA axis.
Hair
Hair analysis is another option for measuring cortisol. It is relatively quick and painless and is a good way to test the function of the HPA axis. The most recent hair growth close to the scalp (the first 3 cm) can provide insights into the patient's cortisol levels over the past three months. The primary advantage of hair testing is its ability to measure stress over time.
Preparing for a Cortisol Test
Before the Test
There are several considerations to be aware of to ensure accurate results.
- Blood draws must be done by a phlebotomist for safety.
- It is essential to drink water. Staying hydrated helps the phlebotomist locate a vein.
- Biotin (vitamin B7) supplements should be avoided before a cortisol blood test.
- Fasting is typically not necessary before this type of test.
- Because there are several cortisol urine tests, check with your provider about instructions before collection.
- For tests that measure cortisol at different times of the day, sleep aids should be avoided for two days, and the test should not be performed during menstruation.
- Fasting may be necessary depending on the timing of the test.
- Certain foods and drinks, including protein powder, nuts, alcohol, bananas, pineapple, avocado, and nicotine, can change the results of the cortisol tests.
- Hormone replacement therapy may change the timing of sample collection.
- Anti-aging skincare should be avoided three days before the test.
- Eating, drinking (except water), and brushing your teeth should be avoided for two hours before the test.
During the Test
Blood draws can be uncomfortable; speak to your phlebotomist about what to expect and strategies to maximize comfort.
Interpreting Cortisol Test Results
Understanding Your Results
Blood Cortisol Test
The normal ranges for a blood cortisol test depend on the time of day and the specific laboratory interpreting the results. Normal ranges include:
- Morning levels: 10-20 mcg/dL
- Afternoon (4 pm): 3-10 mcg/dL
Urine Cortisol Test
Normal cortisol levels in urine depend on gender and age; the normal ranges for a 24-hour urine collection are:
Salivary Cortisol Test
Normal ranges for a saliva test in adults are:
- Morning: 10.2-27.3 ng/mL
- Evening: 2.2-4.1 ng/mL
Hair Cortisol Test
The ranges for hair cortisol concentration include:
- Low levels of stress: 40-128 pg/mg
- High levels of stress: 182-520 pg/mg
A high cortisol level may indicate that the adrenal glands are overproducing or the patient has high stress levels. Low levels may result from Addison's disease (adrenal insufficiency), autoimmune disease, or pituitary insufficiency. Medications, stress, incorrect collection or preparation, and pregnancy can influence results.
Next Steps After Testing
Reviewing cortisol testing results with a doctor and discussing the next steps is essential. If the level is high, further testing may be necessary. If Cushing's disease is suspected, testing may include a nighttime salivary cortisol test or dexamethasone suppression test.
If the cortisol result is low, further testing for Addison's disease, such as a cosyntropin stimulation test, may be ordered. An endocrinologist usually performs additional testing and determines treatment.
Managing Abnormal Cortisol Levels
Treatment Options
High Levels
Several factors cause elevated cortisol levels, and treatment varies. In Cushing's disease or syndrome, surgery may be necessary to remove an adrenal tumor.
Reducing the dose or changing medications may be needed if medications are causing high cortisol levels (e.g., treating asthma with corticosteroids). Common medicines for high cortisol levels include ketoconazole, cabergoline, and pasireotide.
Low Levels
If Addison's disease is the cause of low cortisol levels, hormone therapy may help restore normal levels. Adaptogenic herbs and a higher-sodium diet are complementary treatment options.
Lifestyle Modifications
Several lifestyle modifications are available to support balanced cortisol levels.
- Adequate sleep (7-9 hours for adults) reduces stress and can help reduce cortisol levels.
- Healthy social interactions impact stress levels, and forming a support system can help people cope during stressful times.
- Increasing movement and a healthy diet are effective strategies for dealing with stress and promoting a healthy nervous system.
- Mindfulness and meditation are additional tools for reducing stress and may help promote balanced cortisol levels.
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Key Takeaways
- Cortisol is an important hormone for helping the body respond to stress. It signals the brain when danger is present, but imbalanced levels can cause problems throughout the body.
- Testing through urine, blood, saliva, or hair can provide information about endocrine function and stress levels. It is important to consult a healthcare provider about what test is best for you, proper preparation, result analysis, and any interventions.
- Managing stress through sleep, nutrition, social support, and mindfulness effectively balance cortisol.
- Proactive healthcare involves seeking treatment and testing before a condition worsens. If you have cortisol imbalance symptoms, seek guidance from a healthcare professional for testing and treatment.
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