Evaluating the Accuracy of the Endoscopic ABC Classification System in Diagnosing Helicobacter pylori -Infected Gastritis

Aims: Evaluating the accuracy of the modified Endoscopic ABC (Endo ABC) classification with an electronic endoscopy with narrow band imaging without magnification in diagnosing Helicobacter pylori (H. pylori)-infected gastritis. Methods: A total of 576 patients were enrolled and they underwent modified Endo ABC. They were stratified into 5 groups (A to E) based on the grades of endoscopic findings. H. pylori-infected gastritis status was determined in the following ways: current H. pylori gastritis was defined as active gastritis and/or chronic atrophic gastritis (CAG) seen on endoscopy and positive H. pylori test, naive H. pylori gastritis was defined as regular arrangement of collecting venules in the angle of the lesser curvature without CAG and negative H. pylori test, and previous H. pylori gastritis was defined as negative H. pylori tests regardless of the presence of CAG. Results: Endo A has 97% accuracy and 100% positive predictive value in diagnosing naive H. pylori gastritis. Endo E has 97% accuracy and 100% positive predictive value in diagnosing previous H. pylori gastritis. The accuracy of Endo B and Endo C in diagnosing current H. pylori gastritis was 89 and 82% respectively. Endo D has 87% accuracy in diagnosing previous H. pylori gastritis. Conclusion: This study showed that the modified Endo ABC classification enables to accurately determine the H. pylori-infected gastritis status.