Objective: The endoscopic (13)C-urea breath test ((13)C-EUBT), which combines the urea breath test (UBT) with endoscopy, provides high accuracy for the detection of Helicobacter pylori. This study was conducted to determine whether the (13)C-EUBT using low doses of urea and short sampling times could preserve accuracy in the management of H. pylori infection.
Methods: Three hundred and twenty-five patients were randomized to receive the EUBT with 100, 50 or 25 mg of (13)C-urea by endoscopic spraying. The breath samples collected at 5, 10 and 20 min were analysed using an isotope selected non-dispersive infrared spectrometer. H. pylori infection was assessed by the rapid urease test and histology. In each sampling schedule and protocol, cut-off values were calculated by a receiver operating characteristic curve. We applied the EUBT with 25 mg of (13)C-urea at 5 min to the assessment of eradication in 135 patients who had received the antimicrobial treatment or to the detection of the organism in 61 patients with previous partial gastrectomy.
Results: Based on histology and the urease test, patients who had discordant results were excluded from the analysis. Using 100 mg of urea, the sensitivity and specificity of the test were both 100% at 10 and 20 min, and the sensitivity and specificity at 5 min were best with 98.6% and 100%, respectively. With 50 mg, they were both 100% at 20 min, and the best combination of sensitivity and specificity at 5 and 10 min was 97.3-96.6% and 97.3-100%, respectively. Even with 25 mg, the sensitivity and specificity were both 100.0% at 20 min, and at the 5 min and 10 min time point, the EUBT yielded a sensitivity of 98.7% and a specificity of 100%. There was a significant positive correlation between the test values of the 5 min (13)C-EUBT with 25 mg of test urea and those of the conventional UBT. The 5 min EUBT with (13)C-urea offered high accuracy in the assessment of H. pylori eradication, with the sensitivity and specificity being 100% and 96.4%, respectively. In patients with previous gastrectomy, the EUBT provided acceptable accuracy (a sensitivity of 96.4% and a specificity of 97.0%).
Conclusions: Our results indicate that the (13)C-EUBT is an accurate method for detecting H. pylori infection. The EUBT using only 25 mg of (13)C-urea at the early (5 min) time point has satisfactory diagnostic efficacy in pre- and post-eradication treatment settings, providing a less expensive and more rapid way of performing the test. The EUBT may be a reliable method of assessing H. pylori status in the remnant stomach.