Eosinophilic Esophagitis (EE): Interobserver Variability (IOV) in a Disease Entity in Which Counting Counts
JF Busler, NP Patel, KF Geisinger, ID Hill, KR Geisinger. Wake Forest University School of Medicine, Winston-Salem, NC; University of Nebraska-Lincoln, Lincoln, NE
Background: EE is a clinicopathologic entity characterized by marked eosinophilic infiltrates of the esophageal mucosa, often associated with upper gastrointestinal (UGI) symptoms and endoscopic abnormalities. A major diagnostic criterion is a density of eosinophils (EOS) above which EE is considered likely. Although eosinophilic density is diagnostically crucial, we are unaware of any data evaluating IOV in the counting of EOS in esophageal biopsies (bxs).
Design: To study the reproducibility of counting EOS and thus the diagnosis (dx) of EE, 2 pathologists (A and B) independently counted the highest number of EOS per high power field (HPF) in esophageal bxs from 252 children with upper endoscopy to investigate UGI symptoms. A diagnostic threshold of 20 or more EOS per HPF was used for the dx of EE. In specimens in which there was a diagnostic discrepancy, a 3rd pathologist (C) counted EOS. To assess agreement (above or below the threshold), 2 statistics were computed: the percentage (%) agreement of cases and kappa coefficients.
Results: Pathologists A and B agreed on the presence or absence of EE in 239 cases, for a 94.8% agreement rate. Their kappa statistic was 0.888. 155 biopsies were counted as less than 20 eos per HPF, and 84 were counted as 20 or more. Of the 13 discrepant bxs, pathologist B contributed the higher count in 12 (92%). Pathologist C agreed with A in 4 cases and with B in 9. In 11 cases, C counted 20 or more EOS per HPF.
Conclusions: IOV is excellent with a kappa of 0.888. Thus, bx interpretation of EE has a very low potential level of IOV. Discrepancies usually result from undercounting of EOS.
Wednesday, March 11, 2009 1:00 PM
Poster Session VI # 82, Wednesday Afternoon