13C-urea breath test and gastric mucosal colonization by Helicobacter pylori in children:: Quantitative relation and usefulness for diagnosis of infection

Objective. Because in children Helicobacter pylori colonization could differ as compared to that in adults, gastric metabolism of urea and the reliability of the breath test must be evaluated. The aim of this study was to quantify the relationship between breath test and colonization. Methodology. We studied data from 50 endoscopies performed in 39 children and adolescents (20 girls, 19 boys, aged 3-18 years); 28 were infected with H. pylori. Biopsies were analyzed for histological and microbiological diagnosis of infection and for quantitative antral culture of H. pylori. A C-13 urea breath test was performed on the same day as that of endoscopy (n = 33) or delayed between 2 and 90 days (n = 17). Results. Using a cut-off value of 3 delta %, sensitivity was 96.5%, and specificity was 91.5%. The three children showing discrepancies between breath test and biopsy results had a delta % value close to the cut-off. For the 26 cases with a positive culture, we noted a significant correlation (r = 0.63; p <.001) that was not affected by the delay between breath test and gastroscopy. Conclusion. This quantitative relation between bacterial density and delta % permits increasing the reliability of the test by interpreting carefully those results that approach the cut-off value.