Abstract

Background: To assess the diagnostic value of ¹³C-UBT using capsulated 38 mg low dose for H. pylori infection, we investigated the sensitivity and specificity of ¹³C-UBT and to suggest the optimal positive cut-off value of DOB20 in ¹³C-UBT using ROC analysis. Methods: The study subjects were 76 healthy individuals (males; 52, females; 24) who visited a health promotion center at a university hospital between July 2005 and June 2007. We tested for H. pylori infection by 38 mg low dose ¹³C-UBT and histology. We measured the expiratory ¹³C- urea concentration of basal and 20 minutes value after oral ingestion of 38 mg ¹³C- labelled urea with capsulated. The breath samples were analysed by gas chromatograph isotope ratio mass spectrometer and expressed as units of delta. Results: Fifty subjects (65.8%) were H. pylori positive as judged from histology. ROC analysis showed an area under the curve (AUC) of 0.943 (95% confidence interval: 0.891∼0.995), indicating an excellent classification performance of the model. The sensitivity of 96%, specificity of 85% were achieved at the optimal cut-off value of DOB20 which was 1.39. The 38 mg low dose ¹³C-UBT was a non-invasive, simple, short-time required and highly accurate method. Conclusion: The results suggested that capsulated 38 mg low dose ¹³C-UBT is considered more in term of accuracy, costeffectiveness and convenient method for the diagnosis of H. pylori infection. Further long-term research and meta analysis based on large-scale investigations is needed to establish a standardized testing method in creating protocol of ¹³C-UBT. (J Korean Acad Fam Med 2008;29:788-794)