“…[12][13][14] In the modern era of high-definition endoscopy, the RAC has been confirmed as an important endoscopic predictor of an H pylori-naïve stomach, which is visible by careful observation without the aid of magnification. 15,16 Further mucosal features, including diffuse erythema, 17,18 linear erythema, 17,19 gastric erosions, 19 mucosal oedema, 20 swollen gastric folds, 20 mosaic appearance of mucosa, 18 fundic gland polyps, 19 mucosal atrophy, intestinal metaplasia 21 and gastric antral nodularity, 22 have been proposed to predict H pylori status. These features, and others, have been investigated to varying degrees, using a variety of endoscopic imaging modalities and study designs, and the Kyoto classification of gastritis divides patients into three groups: H pylori naïve (nongastritis), patients with current infection (active gastritis) and patients with past H pylori infection (inactive gastritis).…”