A cortisol blood test measures the level of cortisol, a hormone produced by the adrenal glands, in a person’s blood. Cortisol helps regulate many body functions, including metabolism, immune response, blood pressure, and stress response.

The cortisol blood test is typically ordered to help diagnose and monitor certain medical conditions, including adrenal gland disorders (such as Addison’s disease or Cushing’s syndrome), pituitary gland disorders, and certain types of cancers.

During the test, a small sample of blood is taken from a vein in the arm and sent to a laboratory for analysis. The normal range for cortisol levels in the blood varies depending on the time of day and other factors, but typically falls between 6 and 23 micrograms per deciliter (mcg/dL).

Elevated cortisol levels may indicate the presence of certain medical conditions, including Cushing’s syndrome (a condition where the body produces too much cortisol) and certain types of cancers (such as adrenal tumors). Symptoms of Cushing’s syndrome can include weight gain, high blood pressure, and mood changes. Treatment for Cushing’s syndrome may involve medication to lower cortisol levels and/or surgery to remove the affected gland.

Low cortisol levels may indicate the presence of certain medical conditions, including Addison’s disease (a condition where the body does not produce enough cortisol) and pituitary gland disorders. Symptoms of Addison’s disease can include fatigue, weakness, and weight loss. Treatment for Addison’s disease typically involves hormone replacement therapy to replace the missing cortisol and other hormones produced by the adrenal glands.

It is important to note that the cortisol blood test is only one component of a comprehensive evaluation of the adrenal glands and the endocrine system, and further testing may be required to diagnose or monitor certain medical conditions.