Comparison of the interobserver reproducibility with different histologic criteria used in celiac disease.

Background & Aims: The Marsh–Oberhuber classification of duodenojejunal mucosal lesions is currently used for celiac disease. A more simplified classification, which is based on 3 villous morphologies (A, non-atrophic; B1, atrophic, villous-crypt ratio <3:1; B2, atrophic, villi no longer detectable) and an intraepithelial lymphocyte count of >25/100 enterocytes, has recently been proposed. The aim of the study was to asses the interobserver agreement between different pathologists in classifying celiac disease lesions according to both Marsh–Oberhuber and the new classification system. Methods: Sixty patients were selected for the study: 10 subjects without celiac disease, 13 celiac patients with normal villi but a pathologic increase in intraepithelial lymphocytes >25/100 and hyperplastic crypts, and 37 patients with celiac disease with villous atrophy. Sixty slides were sent to 6 pathologists, who were blinded to each other and were not given any clinical information. Each pathologist received the set of biopsy specimens on 2 separate occasions and had to evaluate them according to both grading systems in a random order. The kappa statistic was used to assess agreement between each pair of pathologists. Results: Overall, mean kappa values were 0.35 (fair) for the Marsh– Oberhuber classification versus 0.55 (moderate) for the new classification system. Conclusions: The new classification for duodenal pathology in celiac disease gives better interobserver agreement compared with the more cumbersome Marsh–Oberhuber classification and contributes to the validity of diagnosis in celiac disease.