POMC and Adrenal insufficiency: The existing controversies in the literature about the use of different Synachten stimulation tests in the assessments of the HPA axis are thought to be related to the use of inappropriate cut-off values.1–5,10–14 Conventionally, adrenal insufficiency is likely if serum cortisol level is less than 18–20 μg/dL (500–550 nmol/L) at 30–60 minutes after administration of ACTH and or an increments of less than 7 μg/dl (200 nmol/L) above basal cortisol, a criterion described by Crowley et al for LDT (10).