title: Hypochlorhydria and achlorhydria are associated with false-positive secretin stimulation testing for Zollinger-Ellison syndrome.
abstract: OBJECTIVE
  Secretin stimulation testing (SST) is used to evaluate patients with hypergastrinemia in the diagnosis of Zollinger-Ellison syndrome. Case series have documented false-positive SST in patients with achlorhydria. This study reviews our experience with SST in hypochlorhydric and achlorhydric patients.
  
  
  METHODS
  We examined 27 patients with hypochlorhydria or achlorhydria based on a predefined basal acid output (BAO) measurement of less than 5.0 mEq/h who also underwent SST for diagnosis of Zollinger-Ellison syndrome. We report the frequency of false-positive SST results in this setting.
  
  
  RESULTS
  Three hundred thirty patients underwent gastric analysis of which 27 had BAO of less than 5.0 mEq/h and SST conducted. The mean (SD) fasting gastrin level was 247 (304) pg/mL, and the mean (SD) BAO measurement was 1.6 (1.8) mEq/h. Twenty patients were off, and 7 were on antisecretory therapy at time of testing. Four patients had false-positive SST results: 3 with gastric atrophy (BAO = 0 mEq/h) and 1 with drug-induced hypochlorhydria (BAO = 0.5 mEq/hr). These false-positive test results were confirmed by structural and functional imaging studies.
  
  
  CONCLUSIONS
  We have identified a 14.8% false-positive rate in SST in patients with hypochlorhydria or achlorhydria. Growing literature has identified severe consequences associated with discontinuing antisecretory treatment for testing; therefore, SST will require interpretation in the setting of gastric acid suppression and needs to be interpreted in this context.
authors.affiliation: Division of Gastroenterology and Nutrition, Memorial-Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Pari
authors.initials: P
authors.lastname: Shah
authors.forename: Maneesh H
authors.initials: MH
authors.lastname: Singh
authors.forename: Yu-Xiao
authors.initials: YX
authors.lastname: Yang
authors.forename: David C
authors.initials: DC
authors.lastname: Metz
mesh_terms: D000126:Achlorhydria / Q000150:complications* / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D000897:Anti-Ulcer Agents / Q000494:pharmacology; D064098:Esomeprazole / Q000494:pharmacology; D005189:False Positive Reactions; D005260:Female; D005744:Gastric Acid / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism; D006801:Humans; D064747:Lansoprazole / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000494:pharmacology; D064750:Rabeprazole / Q000494:pharmacology; D012633:Secretin; D012680:Sensitivity and Specificity; D013270:Stomach / Q000187:drug effects / Q000473:pathology; D055815:Young Adult; D015043:Zollinger-Ellison Syndrome / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D000897:Anti-Ulcer Agents; D064747:Lansoprazole; D012633:Secretin; D064750:Rabeprazole; D009853:Omeprazole; D064098:Esomeprazole