Detection of Helicobacter pylori infection in children with a standardized and simplified 13C-Urea breath test

Background: The C-13-urea breath test, a reliable noninvasive method of detection of Helicobacter pylori in adults, needs validation in children. Methods: in order to evaluate the diagnostic accuracy of C-13-urea breath test in children, the results of this test performed in 144 children were correlated with the histology and culture of contemporaneous gastric (antral and fundic) biopsy specimens. The test was performed with 2 mg/kg body weight C-13-Urea (maximum, 100 mg) ingested after a fat-rich test meal. Samples of expired breath taken at 0, 5, 10, 20, and 30 minutes were assayed with mass spectrometry. Results were considered positive when the curve of excretion of labeled carbon dioxide in the expired breath increased by 5 parts per thousand or more above the baseline. Results: Discrepancies in H. pylori status were observed in 14 children. To improve and simplify the test, the results were reanalyzed using different cutoff values for each sampling time. The best results, with sensitivity of 95.7 parts per thousand and specificity of 95.2%, were obtained with a cutoff of 3.5 parts per thousand at 20 minutes. Conclusions: The C-13-urea breath test is a reliable method for the noninvasive detection of H. pylori infection in children. The test can be simplified and its accuracy improved using only the 0- and 20-minute breath samples and a cutoff of 3.5 parts per thousand instead of the classical 5 parts per thousand used in adults. The need for modi fication of the cutoff value may reflect the higher production of endogenous CO2 in children.