ABC Classification Is Less Useful for Older Koreans Born before 1960.

Background/aims: In the ABC classification system, group A consists of seronegative subjects without gastric corpus atrophy. This study aimed to determine the prevalence and characteristics of pseudo group A subjects.

Methods: Group A subjects were identified among consecutive Korean adults who underwent a serum anti- immunoglobulin G (IgG) test and pepsinogen (PG) assay on the day of endoscopy.