C-13-urea breath test in Helicobacter pylori diagnosis and eradication - Correlation to histology, origin of 'false' results, and influence of food intake

Background: Which protocol is optimal for the C-13-urea breath test (UBT) for Helicobacter pylori detection is controversial. This study aimed to characterize a very simple UBT protocol for the clinical routine (two-point-analysis performed with 75 mg C-13-urea and citric acid) with special consideration of 'false' UBT results. Results: UBT was evaluated in reference to histology (Warthin-Starry). In mismatching results re-gastroscopy was performed. By UBT, 74 of 77 patients with H. pylori-positive histology were detected (sensitivity, 96%). The false-negative UBTs were due to low colonization densities during spontaneous N. pylori elimination or pyloric obstruction. Seven of 49 patients with negative histology had a positive UBT, but re-gastroscopy showed that all of them had a positive histology when multiple antral biopsy specimens were taken (UBT specificity, 100%). UBT correlated only weakly with H. pylori colonization density. No correlation was found between UBT and gastric neutrophil and lymphocyte infiltration. UBT reproducibility was excellent (93 of 94 in a 6-month period). Non-fasting conditions induced a shift to lower UBT results in H. pylori-positive and to higher UBT results in negative patients, resulting in 2 of 10 false-positive and 1 of 10 false-negative UBTs. Conclusion: This simple version of the urea breath test combines the highest sensitivity and specificity with excellent reproducibility. It is superior to histologic detection of H. pylori in the clinical routine and an optimal tool for monitoring H. pylori eradication. Fasting conditions are required for the test.