Lack of Diagnostic Accuracy of the Monoclonal Stool Antigen Test for Detection of Helicobacter pylori Infection in Young Australian Aboriginal Children

Background: The prevalence of Helicobacter pylori infection among Aboriginal Australians children is unclear. The aims of the present study are to determine the prevalence of H. pylori infection among young Aboriginal children recovering from acute diarrheal disease in hospital and to evaluate the H. pylori stool antigen test as a noninvasive diagnostic test in this setting. Methods: This was a prospective comparative study using the 13C-Urea Breath Test as reference standard. Fifty-two children between 4 months and 2 years of age were consecutively enrolled. These children comprised a representative sample of Australian Aboriginal children admitted to hospital with acute diarrheal disease from remote and rural communities across Northern Territory of Australia. Results: The overall prevalence of H. pylori was 44.2%. The stool antigen test had a sensitivity of 0.55 (95% confidence interval CI: 0.35– 0.73) with a positive predictive value of 0.65 (95% CI: 0.42–0.82). The specificity was 0.68 (95% CI: 0.46–0.84) with a negative predictive value of 0.58 (95% CI: 0.39–0.75). Analysis of receiver operator characteristic curve yielded an overall accuracy of the stool antigen test of 61% (48%–75%). Conclusions: The prevalence of H. pylori infection among very young Aboriginal children from remote and rural communities was high and consistent with early acquisition. The diagnostic accuracy of the stool antigen test to diagnose H. pylori in this setting was poor.