Sampling variability on percutaneous liver biopsy in patients with chronic hepatitis C virus infection

Background: Sampling variability on liver biopsy has been demonstrated in a variety of liver diseases. The objective of this study was to determine whether sampling variability exists on percutaneous liver biopsy in patients with chronic HCV infection. Methods: Two separate tissue samples were obtained from the right lobe of the liver, through a single skin puncture, in 29 patients (22 M, mean age 43.4 +/- 8.1 years) with chronic HCV infection. The biopsies were assessed using a descriptive histological reporting system and Knodell's Histological Activity Index (HAI) and compared for differences in necroinflammatory activity (grade) and fibrosis (stage). Results: Thirteen (44.8%) patients had a difference of greater than or equal to1 grade between the 2 biopsies on the descriptive system and 13 differed by greater than or equal to1 stage. On the HAI, 20 (69.0%) patients had a difference of greater than or equal to2 in the necroinflammatory activity score and 10 (34.5%) had a difference of greater than or equal to4; whereas, 11 (38.0%) patients had a difference of greater than or equal to1 in the fibrosis score and 6 (20.7%) had a difference of >2. The mean difference between the two sets of biopsies was 2.4 +/- 2.1 (range 0-7) for the necroinflammatory activity and 0.6 +/- 0.9 (range 0-3) for fibrosis. Spearman's correlation coefficient (r) was moderate for both necroinflammatory activity (r = 0.53, P < 0.01) and fibrosis (r = 0.62, P < 0.0001). Conclusions: Sampling variability exists on percutaneous liver biopsy in patients with chronic HCV infection and should be taken into consideration when decisions regarding prognosis and therapy are made based on biopsy, and when defining histological response to antiviral regimens.