Cortisol, a steroid hormone produced by your adrenal glands, functions as the body’s primary stress hormone. It regulates various bodily processes, including metabolism, blood pressure, and inflammation. Cortisol also helps manage the body’s response to stress by influencing how it utilizes glucose for energy. Imbalances can signal underlying health concerns.
Reasons for Cortisol Testing
A healthcare provider may suggest a cortisol test if you exhibit symptoms that point to either excessively high or low levels of this hormone. Elevated cortisol, often linked to Cushing’s syndrome, can manifest as weight gain, particularly around the face and abdomen, fatty deposits between the shoulder blades, and purple stretch marks on the skin. Other signs may include muscle weakness, fatigue, high blood pressure, elevated blood sugar, acne, and mood fluctuations.
Conversely, symptoms of low cortisol, characteristic of Addison’s disease, include persistent fatigue, unintentional weight loss, and a diminished appetite. Individuals might also experience low blood pressure, dizziness, muscle weakness, and a darkening of the skin.
Understanding Cortisol Test Types
Cortisol levels can be measured through blood, saliva, or urine samples. Blood tests are a common approach, often conducted in the morning when cortisol levels typically peak. These tests usually measure the total amount of cortisol present in the bloodstream.
Saliva tests provide a convenient option, especially for at-home collection, and are useful for assessing the level of “free” or biologically active cortisol. These tests are often collected at specific times, such as late at night, to evaluate the hormone’s natural daily rhythm. Urine tests, typically involving a 24-hour collection, measure the total cortisol output over an entire day, providing a comprehensive picture of the body’s cortisol production.
Where and How to Get Tested
To get your cortisol levels tested, the initial step involves consulting a healthcare provider, such as a general practitioner or an endocrinologist. They can assess your symptoms and medical history to determine if a cortisol test is appropriate and provide a referral. Lab-based tests, including blood and 24-hour urine collections, are performed at medical clinics, hospitals, or commercial laboratories like Quest Diagnostics.
For a blood cortisol test, a sample is usually drawn from a vein, typically in the early morning between 7 and 9 AM. Preparation may involve avoiding strenuous exercise the day before and temporarily stopping certain medications that can influence cortisol levels. A 24-hour urine test requires collecting all urine produced over a full day in a special container.
At-home cortisol test kits, primarily using saliva samples, offer a convenient alternative. These kits are purchased, and you collect samples at specific times, such as late-night, before mailing them to a laboratory for analysis. For saliva samples, it is advised to avoid eating, drinking, or brushing teeth before collection.
Interpreting Your Cortisol Test Results
Cortisol levels naturally fluctuate throughout the day, typically peaking in the early morning, often between 7 and 9 AM, and reaching their lowest point around midnight. This predictable daily rhythm, known as diurnal variation, helps in understanding test outcomes. Standard reference ranges can vary between laboratories, but generally, blood cortisol levels at 8 AM might range from 5 to 25 micrograms per deciliter (mcg/dL) and decrease to 3 to 10 mcg/dL by 4 PM. For 24-hour urine tests, a typical range could be between 10 to 100 mcg per 24 hours.
Elevated cortisol levels may suggest conditions such as Cushing’s syndrome, ongoing stress, or the presence of tumors affecting hormone production. Conversely, lower-than-normal levels might indicate Addison’s disease or issues with the pituitary or adrenal glands. Only a healthcare professional can accurately interpret your results in the context of your specific symptoms and medical history. If your test results are outside the normal range, further consultation with your doctor will be necessary to determine the next appropriate steps for diagnosis and potential management.