Test Details: This test is used to detect excess production of gastrin and gastric acid. It is used to help to diagnose gastrin producing tumours called gastrinomas, Zollinger-Ellison (ZE) syndrome, and hyperplasia of G-cells. G-cells are specialized cells in the stomach that produce gastrin, which in turn increases the production of gastric acid. Zollinger-Ellison (ZE) syndrome is a rare disease of the gastrointestinal tract.