of the disease seen in endoscopic biopsies. The Kyoto system (from the 2015 Kyoto Consensus Conference) classifies gastritis based primarily on the cause and duration of symptoms, resulting in the 3 types: acute, chronic, and special. Gastritis may also be classified based on the kind of mucosal injury, resulting in the 2 types: erosive and non-erosive.

The Operative Link for Gastritis Assessment (OLGA) staging system may also be used to classify cases of gastritis. The OLGA system was devised in an attempt to evaluate complication risk,