CORRELATION BETWEEN PATHOLOGISTS ASSESSING ENDOSCOPIC GASTRIC AND INTESTINAL BIOPSIES USING STANDARDIZED TEMPLATES

Using a set of standardized templates and text (J. Comp. Pathol. 2008; 137:S1-S34), we examined the histologic agreement between four board-certified pathologists who had independently evaluated endoscopic mucosal biopsies of the canine and feline stomach and intestine. Slides from 85 dogs and 41 cats were obtained from 7 institutions, and pathologists scored histological findings (e.g., cellularity, fibrosis, lymphangiectasia) as normal, mild, moderate, or severe. Spearman rank correlation coefficient was used to determine pair-wise correlation between pathologists for variable scores. Fisher’s two-sided exact test was used to test for equality of proportions between pathologists and severity of individual histological signs and between the severity assessments of histological variables and clinical signs. Correlation between pathologists was very weak for eosinophils and neutrophils in the small intestines (-0.081 to 0.404 and -034 to 0.374, respectively) and for small intestinal fibrosis (0.114-0.324). Summary diagnosis of neutrophilic inflammation (-0.033 to 0.169) and lymphangiectasia (-0.039 to 0.252) were also weak but, this may have been primarily due to the low frequency of moderate to severe scores for these two variables. The severity of gastric and duodenal histological findings were not significantly correlated with the assessment of clinical signs or clinicopathologic findings. We conclude that variation in staining and tissue processing may have contributed to (1) lack of agreement between pathologists on eosinophils and neutrophils, and (2) inconsistent ability to assess fibrosis. Standardization of staining and processing is critical to accurate analysis.