More economic 25 mg ¹³C-urea breath test can be effective in detecting primary Helicobacter pylori infection in children

Background and Aim: The high cost of the ¹³C-urea breath test (UBT) limits its wide application for both epidemiological and clinical studies for diagnosing Helicobacter pylori infection. This study examined if a lower-dose UBT, applying 1 mg/kg of bodyweight (maximum 25 mg, UBT ²⁵), could introduce cost savings while preserving high diagnostic yields for primary H. pylori infection. Methods: Children aged less than 16 years were recruited after obtaining consent. Those children with administration of antibiotics or proton pump inhibitors within 1 month of the tests were excluded. Positive tests for both the UBT with 50 mg urea (UBT⁵⁰) and the H. pylori stool antigen (HpSA) were qualifying criteria for H. pylori infection. Negative results for both indicated non-infection. The UBT ²⁵ was conducted 1 week after the UBT⁵⁰. The cut-off points for the UBT²⁵ ranging from 2δ to 5δ were examined for their sensitivity, specificity and accuracy rates. Results: A total of 153 children were recruited (55% male; mean age 9.1 ± 3.5 years). Both the UBT⁵⁰ and HpSA test were positive in 18 (13.1%) and negative in 119 children, respectively. The sensitivity and specificity of the UBT²⁵ were optimally achieved at 88.9% (95% confidence interval [CI]: 71.4-100) and 95.0% (95% CI: 91.1-99.9), judged with a cut-off point at 3.5δ. The diagnostic accuracy was significantly higher for children older than 7 years than for those younger than 7 years (98% vs 85%, P = 0.009). Conclusion: Lower-dose UBT titration by bodyweight can cut costs while maintaining a highly reliable method to screen primary H. pylori infection in children older than 7 years, which is generally beyond school age.