title: Intragastric acidification reduces the occurrence of false-negative urea breath test results in patients taking a proton pump inhibitor.
abstract: OBJECTIVE
  The aim of this study was to investigate whether reducing intragastric pH, at the time of urea ingestion, decreases the likelihood of false-negative (FN) urea breath test (UBT) results in patients taking a proton pump inhibitor (PPI).
  
  
  METHODS
  Patients with active Helicobacter pylori infection underwent a baseline 14C-UBT (UBT-1) followed by treatment with lansoprazole 30 mg/day for 14 to 16 days. On day 13, patients returned for a repeat standard UBT (UBT-2). Between days 14 to 16, patients underwent a modified UBT (UBT-3), which included consuming 200 ml of 0.1 N citrate solution 30 min before and at the time of 14C-urea administration. Breath samples were collected 10 and 15 min after 14C-urea ingestion. Mean 14CO2 excretion and the number of FN and equivocal UBT results were compared for the three UBTs.
  
  
  RESULTS
  A total of 20 patients completed the study. Lansoprazole caused a significant decrease in mean breath 14CO2 excretion (disintegrations per minute) between UBT-1 (2.96 +/- 0.23) and UBT-2 (2.08 +/- 0.52, p < 0.05). Lansoprazole caused six (30%) FN and eight (40%) equivocal UBT-2 results. Mean breath 14CO2 excretion for UBT-3 (677 +/- 514) was greater than for UBT-2 (234 +/- 327, p = 0.001). UBT-3 caused only two (10%) FN and three (15%) equivocal results. The 15-min breath sample caused fewer FN and equivocal results than the 10-min sample for both UBT-2 and UBT-3.
  
  
  CONCLUSIONS
  Giving citrate before and at the time of 14C-urea administration increases mean breath 14CO2 excretion and decreases FN and equivocal UBT results in patients taking a PPI. These observations suggest that it may be possible to design a UBT protocol that will remain accurate in the face of PPI therapy.
authors.affiliation: University of Michigan Health System, Ann Arbor, USA.
authors.forename: W D
authors.initials: WD
authors.lastname: Chey
authors.forename: K V
authors.initials: KV
authors.lastname: Chathadi
authors.forename: J
authors.initials: J
authors.lastname: Montague
authors.forename: F
authors.initials: F
authors.lastname: Ahmed
authors.forename: U
authors.initials: U
authors.lastname: Murthy
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D001944:Breath Tests; D005188:False Negative Reactions; D005260:Female; D005745:Gastric Acidity Determination; D016481:Helicobacter Infections / Q000188:drug therapy / Q000378:metabolism; D016480:Helicobacter pylori; D006801:Humans; D006863:Hydrogen-Ion Concentration; D064747:Lansoprazole; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000627:therapeutic use; D054328:Proton Pump Inhibitors; D012680:Sensitivity and Specificity; D014508:Urea / Q000378:metabolism*
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D054328:Proton Pump Inhibitors; D064747:Lansoprazole; D014508:Urea; D009853:Omeprazole