<prompt> Which of the following does not occur in a patient with gastrinoma -Epigastric painDiarrhoeaBasal acid output BAO less than 15 mEqlitreSerum gastrin levels 200 pgml  <response>: Laboratory Studies in gastrinoma Due to the elusive nature of the neoplasm, the diagnosis is based on the following 3 criteria: Fasting hypergastrinemia is present 150 pgmL with levels 100,000 pgmL in some patients; a serum gastrin level 1,000 pgmL in the appropriate clinical setting is viually diagnostic of Zollinger-Ellison syndrome . Basal acid output BAO is greater than 10 mEqh. Results from a secretin stimulation test are positive. Ref - harrisons internal medicine 20e , Medscape.com 