Factors that affect results of the 13C urea breath test in Japanese patients

Background. The C-13 urea breath test (UBT) is considered to be the most accurate way of diagnosing Helicobacter pylori infection. Our objective was to investigate the accuracy of the UBT in Japanese patients and the association of UBT values with histological findings. Materials and Methods. A total of 169 consecutive patients were studied by endoscopy with histology, by serology with Ige antibody and test serum pepsinogen (PG), and by UBT. The association between UBT values and histological findings and the PG I/II ratio were analyzed in H. pylori-positive patients. Results, Of 169 Japanese patients, 135 were H. pylori-positive on both histology and serology analysis, 27 were H. pylori-negative on both histology and serology analysis, and 7 patients showed differing results. Using a cutoff Value of 2.5 parts per thousand, test sensitivity was 100%, while specificity was 96%. Among the 135 H. pylori-positive patients, a significant relation was observed between UBT value and H. pylori colonization density of the corpus and antrum, neutrophil activity of the antrum, atrophy, and intestinal metaplasia of the corpus in the H. pylori-positive patients. Also, UBT values correlated with the PG Im ratio. In multivariate analysis, the PG I/II ratio was the most important factor related to UBT values (odds ration [OR], 4.99; 95% confidence interval, 1.60-15.55). Conclusions. The UBT is an accurate method for detecting H. pylori infection in the Japanese population, which shows a high prevalence of atrophic gastritis. Values are affected by H. pylori infection and by the severity of atrophic gastritis.