title: Generalizability of the nonalcoholic steatohepatitis Clinical Research Network histologic scoring system for nonalcoholic fatty liver disease.
abstract: OBJECTIVE
  The recently developed histologic scoring system for nonalcoholic fatty liver disease (NAFLD) by the nonalcoholic steatohepatitis (NASH) Clinical Research Network (CRN) is becoming increasingly popular. However, its generalizability to a community setting has not been evaluated. We conducted a study to compare a community general pathologist to an expert hepatopathologist in assessing NAFLD using the NASH CRN scoring system.
  
  
  METHODS
  Forty-eight consecutive patients with suspected NAFLD underwent liver biopsy. Histologic features of interest such as steatosis, lobular inflammation, balloon degeneration, fibrosis, NAFLD Activity Score (NAS), and the presence of NASH were scored in a blinded fashion by the 2 pathologists on 2 separate occasions 3 months apart.
  
  
  RESULTS
  The mean (± SD) length of the liver biopsy samples was 25 ± 5 mm. Interobserver agreement (κ) between 2 pathologists was 0.62 (0.45-0.80) for steatosis, 0.44 (0.23-0.65) for lobular inflammation, 0.25 (0.11-0.38) for ballooning, 0.40 for NAS (0.28-0.52), and 0.35 (0.19-0.52) for fibrosis. The 2 pathologists diagnosed "definite NASH" in a similar proportion of patients (56% vs. 57%), but their interobserver agreement was only 0.46 (0.24-0.67) as they both diagnosed different levels of NASH (borderline vs. definite) in different subjects. Intraobserver agreement was generally comparable for steatosis, lobular inflammation, NAS, and diagnosis of NASH, but not for fibrosis.
  
  
  CONCLUSIONS
  Clinically important differences exist between community general pathologist and expert hepatopathologist in assessing NAFLD using the NASH CRN scoring system. More studies are needed to investigate its suitability for community-based clinical practice.
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202-2859, USA.
authors.forename: Ravi
authors.initials: R
authors.lastname: Juluri
authors.forename: Raj
authors.initials: R
authors.lastname: Vuppalanchi
authors.forename: John
authors.initials: J
authors.lastname: Olson
authors.forename: Aynur
authors.initials: A
authors.lastname: Unalp
authors.forename: Mark L
authors.initials: ML
authors.lastname: Van Natta
authors.forename: Oscar W
authors.initials: OW
authors.lastname: Cummings
authors.forename: James
authors.initials: J
authors.lastname: Tonascia
authors.forename: Naga
authors.initials: N
authors.lastname: Chalasani
mesh_terms: D000328:Adult; D001706:Biopsy; D005234:Fatty Liver / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D006801:Humans; D007249:Inflammation / Q000175:diagnosis / Q000473:pathology; D008099:Liver / Q000473:pathology*; D008103:Liver Cirrhosis / Q000175:diagnosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012720:Severity of Illness Index