Tsachi Tsadok Perets,1,3∗ Einav Shporn,1 Doron Boltin,2,3 Ram Dickman,2,3 and Yaron Niv2,3 1
Gastroenterology Laboratory, Rabin Medical Center - Beilinson Hospital, Petah Tikva, Israel 2Department
of Gastroenterology, Rabin Medical Center - Beilinson Hospital, Petah Tikva, Israel 3Sackler Faculty of
Medicine, Tel Aviv University, Tel Aviv, Israel
Background: The accuracy and repeatability of breath test in the diagnosis of Helicobacter pylori infection
have not been adequately investigated. Although it has been shown that storage for long periods does not
affect the analysis results, no data are available on the effect of repetitive testing. In this study, our aim was
to evaluate the repeatability of the analyses of breath samples at room temperature.
Methods: A total of 202 positive breath samples were collected in duplicates, before and after administration
of 75 mg 13C- urea dissolved in 100 ml of orange juice. Breath test results were expressed as delta 13CO2.
The cut-off value was 3.5 parts per thousand. Each sample was analyzed in a mass spectrometer 7, 14, 21, and
28 days after collection. The accuracy calculation was based on the comparison of the delta 13CO2 obtained
in the three consecutive weeks following the first test run to the delta 13CO2 obtained in the first test run.
Results: Two hundred (99%), 197 (97.52%), and 196 (97%) of the 202 samples tested positive in the second,
third, and fourth test runs, respectively. The accuracy of the delta 13CO2 was 98.6%, 99.2%, and 96.7% in the
three consecutive runs, respectively.
Conclusion: Short-term storage of 1 month does not affect sample stability or the results of 13C-urea breath
tests in up to three consecutive repeats. J. Clin. Lab. Anal. C 2015 Wiley Periodicals, Inc.
Key words: 13C-urea breath test; reproducibility; test accuracy; H. pylori diagnosis; IRMS