Diagnostic practices and variability in autoimmune gastritis: a national survey of gastrointestinal pathologists.

Abstract

Autoimmune gastritis (AIG) is characterized by well-described histologic features, yet diagnostic thresholds and reporting practices vary in routine pathology practice. This study aimed to characterize variability in evaluation, ancillary testing, and reporting of AIG across diverse pathology practice settings and training backgrounds. We conducted a national, anonymized, cross-sectional online survey for practicing pathologists who routinely sign out gastric biopsies. The survey assessed diagnostic criteria for AIG, use of ancillary studies, reporting practices, and approaches to overlapping Helicobacter pylori gastritis. Associations between respondent characteristics and diagnostic behaviors were evaluated using χ2 tests and multivariable logistic regression. A total of 163 pathologists completed the survey. Diagnostic thresholds for AIG varied widely, ranging from strict criteria requiring oxyntic gland atrophy, intestinal metaplasia, and enterochromaffin-like-cell hyperplasia to broader approaches recognizing atrophy alone. Only 22% of respondents reported AIG in the main report, while 43% reported in the comments and only one-third routinely subtyped intestinal metaplasia. In all, 52% of respondents routinely ordered gastrin immunohistochemistry in random gastric biopsies. Academic settings were associated with greater reporting detail, while gastrointestinal pathology fellowship training was associated with the use of qualifying terminology such as "early" or "suspicious" AIG (P = .01). Approaches to cases with concurrent H pylori gastritis and oxyntic gland atrophy also showed substantial variability. Diagnostic evaluation and reporting of AIG remain highly variable and are associated with subspecialty training, practice environment, and years of experience. These findings highlight the need for consensus-based guidance to improve consistency, communication, and clinical integration of AIG diagnoses.