Usefulness of the C-14 urea breath test as a semi-quantitative monitoring instrument after therapy for Helicobacter pylori infection

Background: We evaluated the reliability and usefulness of the C-14 urea breath test (UBT) in confirming eradication of Helicobacter pylori 4 to 6 weeks after cessation of antimicrobial therapy. Methods: We investigated 57 patients, who underwent both an upper endoscopy with multiple biopsy specimens taken for histopathology, culture and/or CLO test, and a C-14 UBT. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the breath test were calculated against the combined biopsy-based test results. Values for sensitivity, specificity, PPV, and NPV were also calculated after excluding results in a grey zone containing equivocal test results. Results: Sensitivity, specificity, PPV, and NPV of the C-14 UBT were 92%, 78%, 52%, and 97%, respectively, After introduction of a grey zone concept, these values were 89%, 100%, 100%, and 97% respectively. Conclusions: We conclude that for research, upper gastrointestinal endoscopy with multiple biopsy specimens and using different diagnostic techniques should remain the 'gold standard' to test for cure.