Validation of a Gastric-Juice-Analysis-Based Approach to H. pylori Diagnosis

Background: Although the incidence of H. pylori infection is decreasing globally, it is not completely negligible. Because H. pylori infection is associated with various pathologies, ranging from peptic ulcer disease to neoplastic lesions, research into and treatment of H. pylori infections remain important. Objectives: We aimed to assess the diagnostic performance of gastric juice analysis (Endofaster®) for the detection of H. pylori in patients undergoing esophagogastroduodenoscopy (EGDS), using conventional histology as the reference standard. Our secondary objectives were to identify the optimal ammonium concentration thresholds for defining positive and negative results and to propose a clinical flowchart to support patient management. Methods: The diagnostic accuracy of Endofaster was first analyzed using an unmatched training cohort comprising an equal number of H. pylori-positive patients (n = 30) and negative controls (n = 30) who underwent EGDS. The derived thresholds were subsequently evaluated in an independent validation cohort of patients who underwent EGDS with Endofaster. Histological examination is the gold standard for H. pylori diagnosis. Results: In the training cohort, an ammonium concentration cut-off of 62 ppm/mL yielded a sensitivity of 90% (95% CI: 74–97%) for ruling out H. pylori infection. For confirming infection, the optimal cut-off was 100 ppm/mL, corresponding to a specificity of 95% (95% CI: 83–99%). Ammonium values > 62 and