title: Influence of liver biopsy heterogeneity and diagnosis of nonalcoholic steatohepatitis in subjects undergoing gastric bypass.
abstract: BACKGROUND
  Nonalcoholic fatty liver disease (NAFLD) is a chronic condition that can progress to cirrhosis and hepatocellular cancer. The most progressive form of NAFLD is nonalcoholic steatohepatitis (NASH). Currently, the only method to diagnose NASH is with a liver biopsy; however. sampling error may limit diagnostic accuracy. We investigated the discordance of paired liver biopsies in individuals undergoing gastric bypass.
  
  
  METHODS
  Two liver biopsies, composite size of > or = 25 mm and > or = 8 portal tracts (PTs), were obtained from the left lobe in 31 subjects. Group 1 included specimens at least 15 mm in length with > or = 4 PTs compared to a second biopsy of at least 10 mm and > or = 4 PTs (Group 2).
  
  
  RESULTS
  The mean specimen size (number of PTs) for group 1 was 20.4 +/- 4.2 mm (11.7 +/- 5.5 PTs) and group 2 was 16.1 +/- 5.3 mm (8.2 +/- 4.1 PTs). Prevalence of NASH was 26% in Group 1 and 32% in Group 2. Sampling discordance was greatest for portal fibrosis (26%), followed by zone 3 fibrosis (13%) and ballooning degeneration (3%). The negative predictive values from Group 1 liver biopsies for NASH and portal fibrosis were only 83% and 67%, respectively.
  
  
  CONCLUSIONS
  The results demonstrate that significant sampling variability exists in class 2 and 3 obese individuals undergoing screening liver biopsies for NAFLD. The degree and histopathological discordance is dependent upon zonal location and types of injury. Nevertheless, a 25-mm biopsy specimen without zone 3 cellular ballooning or fibrosis appears adequate to exclude the diagnosis of NASH.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, University of Alabama, Birmingham, AL 35294, USA.
authors.forename: Janani
authors.initials: J
authors.lastname: Arun
authors.forename: Niraj
authors.initials: N
authors.lastname: Jhala
authors.forename: Audrey J
authors.initials: AJ
authors.lastname: Lazenby
authors.forename: Ronald
authors.initials: R
authors.lastname: Clements
authors.forename: Gary A
authors.initials: GA
authors.lastname: Abrams
mesh_terms: D000328:Adult; D001707:Biopsy, Needle / Q000379:methods*; D015992:Body Mass Index; D015331:Cohort Studies; D005234:Fatty Liver / Q000209:etiology / Q000473:pathology*; D005260:Female; D015390:Gastric Bypass; D006505:Hepatitis / Q000209:etiology / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications / Q000473:pathology* / Q000601:surgery; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results