Acth is adrenocorticotropic hormone, and Acth assay is a test to identify adrenal gland diseases. Acth can be used to identify hypoadrenocorticism and to recognize the type of Cushing’s syndrome. The clinical significance of the Acth assay is that it can identify the presence of symptoms of hypoadrenocorticism and can be used to help make a definitive diagnosis. This diagnosis can be made in patients with mild chronic hypoadrenocorticism and to distinguish secondary chronic hypoadrenocorticism from primary chronic hypoadrenocorticism. The clinical significance of the Acth assay also lies in its ability to identify the type of Cushing’s syndrome, whether it is Acth-dependent or non-Acth-dependent, and other types (pharmacogenetic Cushing’s syndrome), etc. The presence of Acth (pro-adrenocorticism) can also help to identify the type of Cushing’s syndrome. If there is an abnormal Acth (adrenocorticotropic hormone) test, the cause of the disease should be identified and treated.