The early effect of proton pump inhibitor therapy on the accuracy of the 13C-urea breath test

Abstract

Background: The intake of proton pump inhibitors may interfere with the reliability of the urea breath test.

Aim: Prospective study to assess the accuracy of the urea breath test during the first days of therapy with proton pump inhibitors.

Patients: Thirty patients who needed to start proton pump inhibitors therapy and 53 volunteers.

Methods: A 13C-urea breath test was performed respectively before starting proton pump inhibitors therapy and every morning before its intake up until 10 days. The test was considered positive for values of 13CO2 > or = 3.0% delta over baseline. The coefficient of reproducibility for 95% interval of confidence of the urea breath test was calculated in both groups.

Results: Of the 30 patients receiving proton pump inhibitors, 47% were positive for Helicobacter pylori. Among these, 43% developed false negative breath tests in the first 10 days. False positive results occurred in 37.5% of H. pylori-negative subjects in the first 10 days. The coefficient of reproducibility of the urea breath test was significantly higher in the group treated with proton pump inhibitors (11.0 versus 1.8 for the control group, p < 0.0001).

Conclusion: The intake of proton pump inhibitors impairs the accuracy of the 13C-urea breath test. False negative and false positive 13C-urea breath tests are common, occur as soon as after 1 day and increase with prolonged duration of treatment. The coefficient of reproducibility of the test in patients receiving proton pump inhibitors is not acceptable for clinical purpose and the test should not be performed once the medication has been started.