Diagnostic Criteria for Zollinger-Ellison Syndrome (ZES)

Diagnostic criteria for ZES include the following:

  1. Elevated levels of Basal Acid Output (BAO), greater than 15 mEq in unoperated patients and greater than 5 mEq if previous acid-reducing surgery has been performed;
  2. Elevated level of fasting serum gastrin (>100 pg/mL until 1994, >200 pg/mL since 1994);
  3. Abnormal results from stimulation testing with secretin (an increase of >200 pg/mL postinjection) or with calcium (an increase >395 pg/mL);
  4. Positive histologic confirmation of gastrinoma; or
  5. A combination of these criteria. Continue reading