Clinical significance of oral urease in diagnosis of Helicobacter pylori infection by [C-13]urea breath test

This study was performed to evaluate the effect of oral flora on [C-13] ure a breath test in detecting H. pylori infection and find an optimal method a nd timing for sample collection. Forty-five volunteers were included in thi s study. The [C-13] urea breath test was performed using mouthwash, endosco pic administration, and conventional methods. According to the receiver-ope rating characteristic curves, the earliest optimal time for discriminating H. pylori-positive and H. pylori-negative patients was at 25 min with the mouthwash method with 78% sensitivity and 82% specificity, at 2 min with th e endoscopic administration method with 100% sensitivity and 100% specifici ty, and at 6 min with the conventional method with 100% sensitivity and 95% specificity. The study shows a significant effect of oral urease on the re sults of the [C-13] urea breath test. The timing of sampling collection can be shortened to 6 min with the conventional method or to 2 min through end oscopic administration.