Comparison of the Low Dose Short Synacthen Test (1 μg), the Conventional Dose Short Synacthen Test (250 μg), and the Insulin Tolerance Test for Assessment of the Hypothalamo-Pituitary-Adrenal Axis in Patients with Pituitary Disease

There is still uncertainty about what is the most appropriate test for assessment of the integrity of the hypothalamo-pituitary-adrenal (HPA) axis. Many advocate the insulin tolerance test (ITT), but this is unpleasant and resource intensive, and may occasionally give misleading results. The conventional [250 μg tetracosactrin, ACTH-(1–24)] short synacthen test (SST) has been used as a simple alternative to the ITT, but it has produced some falsely reassuring results with potentially serious consequences. A low dose [1 μg tetracosactrin, ACTH-(1–24)] short synacthen test (LDSST) has recently been advocated as a more reliable and safer alternative to ITT. Some studies, however, have failed to demonstrate any difference between SST and LDSST. The purpose of this study was to assess the clinical usefulness of LDSST compared to SST and ITT in patients with pituitary disease. We studied 64 patients with suspected or proven pituitary disease. All patients underwent SST and LDSST. Forty-two patients underwent IT...