Back Blood-tests Explained


ACTH


At a Glance

Why Get Tested?

In conjunction with cortisol testing, to help diagnose adrenal gland problems and pituitary diseases such as Cushing syndrome, Cushing disease, Addison disease, adrenal tumors, and pituitary tumors

When to Get Tested?

When you have signs and symptoms associated with excess or deficient cortisol production; when your healthcare provider suspects that you have a hormone imbalance that could be caused by a problem with your pituitary or adrenal glands

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

The healthcare practitioner may request that you fast overnight before testing. Blood is typically drawn in the morning, about 8 a.m.

The Test Sample

What is being tested?

Adrenocorticotropic hormone (ACTH) is a hormone that stimulates the production of cortisol. Cortisol is a steroid hormone made by the adrenal glands that is important for regulating glucose, protein, and lipid metabolism, suppressing the immune system's response, and helping to maintain blood pressure. This test measures the amount of ACTH in the blood.

ACTH is produced by the pituitary gland. Located below the brain in the center of the head, the pituitary gland is part of the endocrine system, a network of glands that work together to produce hormones that act on organs, tissues, and other glands to regulate systems throughout the body.Feedback system between hypothalamus, pituitary and adrenal glands

Normally, ACTH levels increase when cortisol is low and fall when cortisol is high. In response to a fall in the blood cortisol level, the hypothalamus produces corticotropin-releasing hormone (CRH). This stimulates the production of ACTH by the pituitary, which in turn stimulates the production of cortisol by the adrenal glands, small organs located at the top of each kidney. To make the appropriate amounts of cortisol, the hypothalamus, pituitary, and adrenal glands must be functioning properly.

Conditions that affect the hypothalamus, pituitary, or adrenal glands can interfere with regulating ACTH and cortisol production, increasing or decreasing how much of the hormones the glands produce. This can cause signs and symptoms associated with an excess or deficiency of cortisol. Conditions that affect ACTH include Cushing disease, Addison disease, and hypopituitarism. Some tumors found outside of the pituitary in locations such as the lungs can also increase cortisol concentrations by producing ACTH.

How is the sample collected for testing?

A blood sample is drawn by needle from a vein in the arm.

Is any test preparation needed to ensure the quality of the sample?

The healthcare practitioner may request that you fast overnight before testing. Blood is typically drawn in the morning, about 8 a.m.

The Test



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