|
The ACTH test (also called the cosyntropin, tetracosactide, or Synacthen test) is a medical test usually ordered and interpreted by endocrinologists to assess the functioning of the adrenal glands stress response by measuring the adrenal response to adrenocorticotropic hormone (ACTH; corticotropin) or another corticotropic agent such as tetracosactide (cosyntropin, tetracosactrin; Synacthen) or alsactide (Synchrodyn). ACTH is a hormone produced in the anterior pituitary gland that stimulates the adrenal glands to release cortisol, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEA-S), and aldosterone. During the test, a small amount of synthetic ACTH is injected, and the amount of cortisol, and sometimes aldosterone, the adrenals produce in response is measured. This test may cause mild to moderate side effects in some individuals. This test is used to diagnose or exclude primary and secondary adrenal insufficiency, Addison's disease, and related conditions.〔 In addition to quantifying adrenal insufficiency, the test can distinguish whether the cause is adrenal (low cortisol and aldosterone production) or pituitary (low ACTH production).〔 The ACTH stimulation test is recognized as the gold standard assay of adrenal insufficiency, although this test is primarily used to determine the presence of Addison's disease and pituitary impairment. The test is extremely sensitive (97% at 95% specificity) to primary adrenal insufficiency, but less so to secondary adrenal insufficiency (57-61% at 95% specificity); while secondary adrenal insufficiency may thus be dismissed by some interpreters on the basis of the test, additional testing may be called for if probability of secondary adrenal insufficiency is particularly high.〔 Adrenal insufficiency is a potentially life-threatening condition. Treatment should be initiated as soon as the diagnosis is confirmed, or sooner if the patient presents in apparent adrenal crisis. ==Versions of the test== This test can be given as a ''low-dose short test'', a ''conventional-dose short test'', or as a ''prolonged-stimulation test''. In the low-dose short test, 1 µg of an ACTH drug is injected into the patient. In the conventional-dose short test, 250 µg of drug are injected. Both of these short tests last for about an hour and provide the same information. Studies have shown the cortisol response of the adrenals is the same for the low-dose and conventional-dose tests. The prolonged-stimulation test, which is also called a ''long conventional-dose test'', can last up to 48 hours. This form of the test can differentiate between primary, secondary, and tertiary adrenal insufficiency. This form of the test is rarely performed because earlier testing of cortisol and ACTH levels in association with the short test may provide all the necessary information.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ACTH stimulation test」の詳細全文を読む スポンサード リンク
|