New Cut-off Value for Low-Dose Acth Stimulation Test in the Diagnosis of Adrenal Insufficiency

Aim:Although the peak cortisol response in the low-dose test does not reach the generally accepted value of 18 μg/dL, there are many patients whose adrenal insufficiency diagnosis was ruled out by getting an adequate response with the standard-dose test. Thus, the standard-dose adrenocorticotropic hormone (ACTH) stimulation test is unnecessarily applied to many patients. This study aims to compare low- and standard-dose ACTH stimulation tests in diagnosing adrenal insufficiency and to determine a new optimal threshold level for low-dose ACTH stimulation tests to avoid unnecessary standard-dose ACTH tests.Methods:In this single-center cross-sectional study, patients with suspected adrenal insufficiency who underwent low-dose (1 mcg) and standard-dose (250 mcg) ACTH stimulation tests were evaluated. Cases were separated into two groups: (I) inadequate cortisol response (