SCT and gastrin-producing neuroendocrine tumor: Current guidelines recommend the combination of hypergastrinemia and basal gastric acid hypersecretion (pH < 2).14, 15 Gastrinoma diagnosis frequently differs from these criteria, because of the lack of gastric pH measurement, the unavailability of secretin testing and the use of immunohistochemistry and imaging as alternatives.26 In daily clinical practice of the DMSG, gastrinoma diagnosis was complicated by the unavailability of stimulation tests, no routine measurements of gastric pH and widespread use of PPI.