Effect of proton pump inhibitors on the continuous real time ¹³C-urea breath test

OBJECTIVE: The aim of this study was to evaluate the accuracy of a new, continuous real time ¹³C-urea breath test, BreathID, for the diagnosis of Helicobacter pylori in patients taking proton pump inhibitors (PPIs). METHODS: Fifty-two consecutive patients, positive for H. pylori by BreathID, were prospectively evaluated. Patients were randomized to receive either omeprazole 20 mg/day or pantoprazole 40 mg/day for 14 days. A repeat breath test was performed on day 14 while patients received their last PPI pill. Patients were given a test drink containing 75 mg ¹³C-urea and 4.0 g citric acid. Real time, continuously sampled expired ¹³CO₂, obtained within 6-20 min, was compared with measurement of expired ¹³CO₂ by isotope ratio mass spectrometry (IRMS). RESULTS: A full set of test data was available for 43 patients. After 14 days of treatment with PPIs, false negative detection of H. pylori occurred in only 1/43 (2.3%) patients examined by continuous real time ¹³C-urea breath test compared with 2/43 (4.6%) patients examined by IRMS. With the exception of one case, complete agreement was observed between BreathID and the IRMS breath tests at both baseline and after PPI treatment. PPI treatment was associated with three different types of responses on UBT: 1) one third of the patients developed a significant decrease in the ¹³CO₂/¹²CO₂ excretion, 2) roughly one third developed a significant increase in the post-PPI breath test results, and 3) results did not change significantly in the remaining patients. Linear regression analysis of 43 H. pylori-positive subjects indicated a significant positive association between baseline and post-PPI Δ ¹³CO₂¹²CO₂ excretion. CONCLUSIONS: The use of a single test drink containing 4.0 g citric acid in BreathID, resulted in a low number of false negative results associated with sustained PPI treatment. Although there were some differences between BreathID versus IRMS, the type of PPI and the sampling method used do not appear to play a critical role in the detection of H. pylori by BreathID. According to these results, BreathID is a reliable tool for testing H. pylori in patients taking PPIs.