Current or recent proton pump inhibitor therapy markedly impairs the accuracy of the [14C]urea breath test

Eur J Gastroenterol Hepatol. 1998 Sep;10(9):759-64. doi: 10.1097/00042737-199809000-00006.


Background: There are increasing indications for assessing Helicobacter pylori status by non-invasive means in dyspeptic patients. There is also increasing use of proton pump inhibitor therapy for dyspeptic disease.

Aims: To determine the effect of proton pump inhibitor therapy on the accuracy of the [14C]urea breath test.

Patients: [14C]Urea breath tests were performed in 20 H. pylori-positive and 13 H. pylori-negative dyspeptic patients before commencing omeprazole and after 4 weeks of treatment with 40 mg/day and then 6 months of treatment with 20 mg/day. Further studies were done in H. pylori-positive patients to examine the time course of the onset and resolution of the effect observed.

Results: False negative results occurred in 45% of the H. pylori-positive subjects after 4 weeks of omeprazole 40 mg/day and in 28% after 6 months of 20 mg/day. False positive results occurred in 15% of the H. pylori-negative subjects after 4 weeks of omeprazole 40 mg/day. In the H. pylori-positive subjects time course studies showed increasing suppression of the breath test result over the first 2-4 weeks of treatment. It took a similar time for the breath test result to recover after stopping treatment. There was no significant change in H. pylori IgG serology in the H. pylori-positive patients after 7 months of omeprazole treatment.

Conclusions: Proton pump inhibitor therapy markedly impairs the accuracy of the [14C]urea breath test and, in particular, produces a high proportion of false negative results. The effect is dose related and may persist for 2-4 weeks after stopping therapy. Patients should be carefully questioned about recent proton pump inhibitor therapy before accepting a negative breath test result as reliable.

MeSH terms

  • Anti-Ulcer Agents / therapeutic use*
  • Antigens, Bacterial / blood
  • Breath Tests*
  • Dyspepsia / drug therapy
  • False Negative Reactions
  • False Positive Reactions
  • Helicobacter Infections / blood
  • Helicobacter Infections / immunology
  • Helicobacter pylori / isolation & purification
  • Humans
  • Immunoglobulin G / blood
  • Omeprazole / therapeutic use*
  • Proton Pump Inhibitors*
  • Sensitivity and Specificity
  • Time Factors
  • Urea / analysis*


  • Anti-Ulcer Agents
  • Antigens, Bacterial
  • Immunoglobulin G
  • Proton Pump Inhibitors
  • Urea
  • Omeprazole