ACTH levels are associated with cortisol levels in the blood. These levels are usually measured to check and monitor any conditions that are associated with increased or decreased cortisol levels in the blood. Some of the diseases associated with abnormally high cortisol levels include Cushing's disease and Cushing’s syndrome. Decreased cortisol levels are usually associated the Addison’s disease, adrenal insufficiency, and hypopituitarism.
Once the ACTH levels are determined, the doctor usually prescribes a test to check the blood cortisol levels as well. This helps in differentiating between the cortisol -related diseases and distinguishing the right cause for the condition. ACTH stimulation test is designed specifically as a screening test and further testing is usually required to make a definitive diagnosis.
The ACTH stimulation test protocol is usually very simple. Blood is drawn from a vein and then tested in the laboratory for ACTH levels. The ACTH levels usually increase with decrease in cortisol levels and vice-versa. This inversely proportional relationship between cortisol and ACTH can be helpful in diagnosing exact medical conditions.
Usually, ACTH test is ordered when a patient becomes symptomatic and has specific signs. Some of the symptoms of excessive cortisol or low levels of ACTH include obesity, with the weight usually concentrated on the trunk region and not the limbs. The person may have a rounded face, thin skin that is very fragile, purple marks on the abdominal region, weakness in the muscles, acne, and excessive hair on the body. Apart from this, people with high levels of cortisol may also have high blood pressure, high levels of bicarbonate, low potassium, diabetes, or generally high levels of blood glucose. People with low levels of blood cortisol may experience fatigue, muscle weakness, unexplained weight loss, loss of appetite, and increased skin pigmentation. The ACTH stimulation test results, along with the symptoms experienced by the person may help the doctor reach a diagnosis.
The ACTH stimulation test side effects are similar to the side effects of any blood test. There may be redness and swelling at the site from where blood is taken. Some people may also experience excessive bleeding due to lack of clotting. The ACTH stimulation test cost is different from one laboratory to another. The reference ranges for blood cortisol and ACTH are also different for different diseases. The test results are best evaluated by a lab technician or a doctor, who can then diagnose the problem and recommend a treatment plan.