OBSERVER VARIATION IN THE ASSESSMENT OF CHRONIC GASTRITIS ACCORDING TO THE SYDNEY SYSTEM

The main aims of the Sydney system for the classification of gastritis are to improve uniformity in histopathological reporting and to provi de a flexible matrix of rules for grading the histological, features. We sought to determine the level of interobserver agreement between pa thologists in the application of the Sydney system. Three histopatholo gists independently examined H & E, alcian blue/PAS and modified Giems a stained sections of two antral and two corpus gastric biopsies from 69 consecutive dyspeptic patients. After elimination of five unsuitabl e cases, each observer graded chronic inflammation, polymorph activity , atrophy, intestinal metaplasia and Helicobacter pylori density in th e antrum and corpus on a 0-3 scale according to the Sydney system crit eria. The pairwise agreement on final diagnosis and the overall and co nditional agreement on histological grades were examined by kappa stat istics. Agreement on the final diagnosis ranged from 83-94% with kappa values of 0.699 ('good') to 0.887 ('excellent'). Conditional probabil ity of agreement on a diagnosis of H. pylori positive gastritis was 99 %, but wider disagreements were apparent in the recognition of H. pylo ri negative gastritis, reactive gastritis and even normal biopsies. Ov erall agreement for grade ranged from 70% for antral atrophy to 94% fo r intestinal metaplasia in the corpus with 'moderate' or 'good' kappa values. We conclude that the diagnostic and grading criteria described in the Sydney system can be applied consistently by histopathologists . The findings underline its potential usefulness in routine practice.