Limitations to carbon 13-labeled urea breath testing for Helicobacter pylori in infants

We determined the validity of the carbon 13-labeled urea breath test in young children. We found that although the C-13-labeled urea breath test had a specificity greater than 90%, borderline or false positive results occurred more frequently in children younger than 2 years compared with older children. False positive results may be caused by oral-urease-producing organisms because direct intragastric administration of C-13 urea reduced the excess delta (CO2)-C-13. Care is urged in interpreting one positive C-13-Iabeled urea breath test in children younger than 2 years.