<prompt> A 45-year-old gentleman has undergone truncal vagotomy and pyloroplasty for bleeding duodenal ulcer seven years ago. Now he has intractable recurrent symptoms of peptic ulcer. All of the following suggest the diagnosis of Zollinger Ellison syndrome, except:Basal acid output of 15 meqhourSerum gastrin value of 500 pgmlUlcers in proximal jejunum and lower end of esophagusSerum gastrin value of 200 pgml with secretin stimulation  <response>: Diagnosis of ZES is made by secretin provocative test when serum gastrin value increases 200 pgml, within 15 minutes Zollinger Ellison syndromeZES is caused by gastrin secreting gut neuroendocrine tumors gastrinomas, which result in hypergastrinemia and acid hypersecretion.Clinical situations that create suspicion for ZES areulcers in unusual locations, ulcers in second part of duodenum beyond includes the option culcers refractory to standard medical therapyulcer recurrance after acid reducing surgery.ulcers presenting with frank complications bleeding, perforation and obstruction ulcers in the absence of H. pylori or NSAID ingestion.giant ulcers 2 cmmultiple duodenal ulcersulcers associated with diarrhoeaulcer patient with hypercalcemia or family ho ulcers.ulcers with severe esophagitis.ulcers associated with prominent gastric foldsulcers with findings so MEN-1 endocrinopathy, family ho ulcers or endocrinopathy, nephrolithiasisDiagnosis of ZES gastrinomaThe first step in evaluation of a patient suspected of having ZES or gastrinoma is to obtain as fasting gastrin level.All gastrinoma patients have a fasting gastrin level 150 pgmL.The next step is to assess acid secretion by measuring basal acid output BAD which should be 15 meqh normal 4 meqhA gastric pH of 3.0 implies hypochlorhydria and excludes gastrinoma.Gastrin Provocative testsIn a pt. with pH 2.0 or BAO 15 meqhr and fasting gastrin level 1000 pgmL, the diagnosis of LES is confirmed.With pH 2.0 or BAO 15 meqL and lower gastrin levels 150-1000 pgmL, a secretin stimulation test is perforfmed to distinguish LES from other causes of hypergastrinemia.A rise of 200 pgmL of serum gastrin level within 15 min of secretin injection, confirms ZES. 