The ACTH challenge test is a test used to determine the functioning of the pituitary gland which relates to the release of the hormone known as ACTH or Adrenocorticotrophic Hormone. This hormone ACTH is released by the pituitary gland in order to stimulate the production and release of cortisol. Cortisol is a steroid that is released during periods when the body may be under stress. Cortisol is produced by the adrenal glands which are located near the kidneys.
The ACTH test is a test used to check if the problem of low cortisol production is being caused by insufficient ACTH or is being caused by an insufficient reaction of the adrenal glands to the hormone ACTH. The test begins with a simple blood draw procedure. The patient’s blood is tested for the level of cortisol and for the level of the hormone ACTH. Once these base values are established, the patient is given an injection which contains synthetic ACTH. After about an hour, the blood of the patient will be drawn again. This blood is tested for the level of cortisol.
After the ACTH challenge test, the patient is diagnosed as having normal function or of having abnormal function either in the adrenal glands or of the pituitary gland that actually controls the functions of these glands. When the patient suffers from excessive cortisol in the body, there will be numerous different symptoms. These symptoms include thin skin, obesity and muscle weakness amongst others. Patients who do not have enough cortisol released into their blood will suffer from muscle weakness, fatigue and weight loss or an inability to gain weight. As one can imagine, these symptoms are rather vague and do not necessarily point towards any medical condition. Therefore, an individual will probably be given a broad spectrum blood test to check for various different hormone and steroid levels. When this initial test shows an improper cortisol level, the patient may be asked to undergo an ACTH challenge test. This will establish to reason behind the development of the problem in the first place. Further testing may be necessary once the problem gland or glands have been identified. These may include imaging tests or further blood tests.
The ACTH challenge test is also known as the ACTH stimulation test. This is because the ACTH stimulation test is used to encourage the adrenal glands to perform their cortisol secretion function properly.