Accuracy of breath tests using low doses of 13C-urea to diagnose Helicobacter pylori infection: a randomised controlled trial

Background: A new 13C UBT consisting of a tablet formulation (TB) of 13C-urea with citric acid (CA) has been described. It allows breath sampling to be performed as early as 10 minutes after ingestion of the tablet. Aim: to assess the diagnostic accuracy of 13C TB UBT containing 50 and 100 mg of 13C-Urea plus CA in pre and post treatment, compared to a biopsy based gold standard and a conventional liquid UBT using 75 mg of 13C-urea. Patients and methods: 200 dyspeptic patients underwent endoscopy with biopsies followed by a conventional 13C-UBT, 100 mg and 50 mg TB 13C-UBTs performed on the next three days. Infected patients were prescribed an active treatment and asked to come back 4-6 weeks after the end of treatment to repeat endoscopy and UBTs. Results: 113 patients were H pylori infected. The sensitivity and specificity of the conventional UBT were 100%; the sensitivity and specificity for 100 mg TB were 100% and 98.85%. For the 50 mg TB, cut-off values of DOB between 1.65 and 3.15 provided a sensitivity and specificity of 100%. 109 out of 113 positive patients were available at follow-up and 23 were still infected. The sensitivity and specificity of the conventional UBT and of 100 mg TB were 100%. For the 50 mg TB UBT, cut-off values of DOB between 1.49 and 1.56 gave a sensitivity and specificity of 100%. Conclusion: new 100 and 50 mg TB 13C-UBTs are reliable tools to assess H pylori status in pre and post treatment