Background & aims: Assessment of liver histology has an important role in the management of chronic liver disease. It is not clear whether there are interobserver variabilities between hepatopathologists and general community pathologists. We evaluated the effect of type of pathologist and biopsy specimen size on interobserver agreement for hepatic fibrosis.
Methods: Subjects were identified from a population-based sample of adults from a chronic liver disease surveillance network. Biopsy slides from 391 hepatitis C patients who had undergone liver biopsy were obtained and read by 2 study hepatopathologists blinded to the patients' diagnoses (the gold standard). The interobserver agreement of the fibrosis stage between the hepatopathologists and the general pathologists' report were evaluated by kappa index.
Results: There was complete agreement between the study pathologist and community pathologist in 49.9% of biopsy specimens. The overall kappa index across all stages of fibrosis was 0.409, with the best agreement occurring at higher stages of fibrosis (kappa: 0.482 for stage 3, 0.776 for stage 4). Overall agreement was good (kappa, 0.465) when biopsy samples were greater than 1.5 cm in size. The community pathologist understaged fibrosis in 73% of biopsy specimens with disagreement. A total of 26% of patients with stages 2 to 4 fibrosis were understaged by the community pathologist.
Conclusions: Results from this population-based study show good overall interobserver agreement between hepatopathologists and general pathologists when determining fibrosis stage in liver biopsy specimens from hepatitis C patients when liver biopsy sizes are adequate. However, community pathologists tended to understage fibrosis, which could keep patients from receiving proper treatment.