Adrenocorticotropic Hormone (ACTH) Blood Test

The ACTH blood test evaluates symptoms associated with excess or deficient cortisol.

Description

The adrenocorticotropic hormone (ACTH) blood test identifies symptoms related to the excess or deficiency of cortisol. ACTH is a hormone that is produced in the hypophysis and is often caused by stress. Cortisol is a steroid hormone in the adrenal gland that helps reduce stress effects on the human body. Since the ACTH level typically changes in the opposite direction to the cortisol level, a great deal can be learned by identifying an imbalance in this relationship and how the imbalance occurs.

ACTH blood tests are often ordered if a patient shows signs or symptoms of cortisol excess or deficiency, such as:

• fatigue
• weight loss or gain
• fragile skin
• high or low blood pressure
• purple streaks or lines on the abdomen
• muscle wasting and other varied symptoms

This test is a convenient and inexpensive way to identify excess and deficient levels of cortisol that can lead to more severe health problems such as Addison's disease, adrenal disorder, and Cushing 's syndrome.

Blood cortisol tests are ordered if a patient has symptoms related to cortisol deficiency or excess. The measurement of both ACTH and cortisol levels can help to distinguish between some of these conditions. Often excessive cortisol levels cause:

• weight issues such as obesity (especially in the trunk area, and not in the arms and legs)
• acne
• muscle weakness
• increased body hair
• a rounded face
• fragile and thin skin
• purple lines on the abdomen

Low potassium, high blood pressure, high glucose (sometimes diabetes), and high bicarbonate are often associated with excess cortisol.

Patients with insufficient production of cortisol can have the following symptoms:

• fatigue
• weight loss
• loss of appetite
• increased skin pigmentation (even in areas not exposed to the sun)
• muscle weakness

Low sodium, low blood pressure, high calcium, low blood glucose, and high potassium are often associated with low cortisol levels.

When a pituitary tumor( typically benign) causes the condition, the patient may also have symptoms associated with compression of nearby nerves and cells. The tumor may also affect nerves that control vision and cause "tunnel vision" (incapacity to see things off to the side), vision loss to particular localized areas or double vision, and possibly create a change in a consistent pattern of headaches.