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

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.

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

[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.

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.

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.