LOW-DOSE ACTH STIMULATION TEST

Most symptoms and signs of adrenal insufficiency are nonspecific yet c ommon, Because the disorder is life threatening but very easy to treat , it is essential that it be accurately diagnosed. A test that is simp le, inexpensive, and accurate is needed for this purpose. The tests av ailable in the past were either expensive and not readily available (c orticotropin releasing hormone), symptomatic and necessitating hospita lization (metyrapone or insulin tolerance), or not always reliable (AC TH stimulation). This last test, although easy to perform and inexpens ive, uses extremely hyperphysiologic doses of ACTH to evaluate a physi ologic response, This can cause false negative results, many of which are published in the literature. A physiological dose ACTH test, 1.0 m u g, has been developed that is more sensitive than the original test in cases of mild adrenal insufficiency. It is also a very sensitive wa y to assess pituitary-adrenal suppression after long-term treatment wi th glucocorticosteroids. In this situation, symptoms of the basic dise ase for which steroids were administered and withdrawal symptoms often complicate the picture. The 1.0 mu g ACTH test is as sensitive as the insulin tolerance test and metyrapone tests and should be used as the screening test for adrenal insufficiency whenever such testing is ind icated.