Diagnosis and differential diagnosis of hypergastrinemia.

The most frequent conditions of hypergastrinemia in man are the Zollinger-Ellison syndrome with autonomous gastrin hypersecretion by the tumour cell and reactive hypergastrinemia in type A autoimmune chronic atrophic gastritis with achlorhydria causing unrestrained gastrin release from the gastrin-producing antral G-cells. Both entities differ with respect to the pH in the gastric fluid, which is < 2 in patients with Zollinger-Ellison syndrome and neutral in type A gastritis. Other conditions with moderate hypergastrinemia as treatment with proton pump inhibitors, gastric outlet obstruction, previous vagotomy, chronic renal failure or short bowel syndrome are of minor clinical importance.