Sources of variability in histological scoring of chronic viral hepatitis†

Abstract

Inter-observer agreement on activity and fibrosis scores used in chronic viral hepatitis has only been studied under selected conditions. The aim of this study was to identify the sources of variability due to specimen characteristics and observers. This study included 254 liver specimens and 15 pathologists and used the Metavir score. In 44 specimens scored by 4 academic pathologists, agreement of Metavir score was good overall, but better for fibrosis ( ‫؍‬ 0.59) than for activity ( ‫؍‬ 0.43) and poor for lobular necrosis ( ‫؍‬ 0.15). The mean agreement was better for senior (0.60 ؎ 0.24) than junior pathologists (0.52 ؎ 0.30, P < .05). Mean intrabserver agreement was better than inter-observer agreement (0.77 ؎ 0.18 vs. 0.58 ؎ 0.26, P < .01). In 157 specimens scored by 2 expert pathologists (one senior, one junior), agreement of Metavir score was only good but greatly improved after consensus reading (fibrosis: ‫؍‬ 0.48 and 0.77, activity: ‫؍‬ 0.44 and 0.70, respectively, before and after consensus). Several causes of disagreement were identified: specimen length, fibrosis class number, observer bias, and putative causes related to Metavir score or specimen. In an intercenter evaluation involving 59 specimens, 1 expert and 10 nonacademic pathologists, agreement was very poor and did not improve over 5 years for activity ( ‫؍‬ 0.22-0.25) or fibrosis ( ‫؍‬ 0.13-0.18). In conclusion, the level of experience (specialization, duration, and location of practice) has more influence on agreement than the characteristics of the specimen (length, fibrosis class number, miscellaneous factors). Agreement can be improved by experienced pathologist or consensus reading. (HEPATOLOGY 2005;41:257-264.)

Hepatic venous pressure gradient identifies patients at risk of severe hepatitis C recurrence after liver transplantation

“…Although underestimation of liver damage occurs in small specimens, 11 the level of experience of the pathologist is also relevant for diagnostic accuracy. 12 HVPG measurement (and TLB) has some limitations. First, it is an invasive and expensive procedure, which is of concern, particularly if it needs to be repeated during follow-up.…”

“…Needle biopsy specimens represent an extremely small part of the liver and for this reason sample errors are frequent. 11,12 More importantly, underestimation of liver damage might become a relevant issue in individuals with rapid disease progression, such as HCV-infected liver transplant recipients.…”

Non-invasive assessment of liver fibrosis in chronic hepatitis C

“…However, liver biopsy is an invasive procedure, associated with pain in around 30% of cases [3][4][5], and potentially life-threatening complications (hemorrhage in 0.3% of cases and mortality in 0.01%) [6]. The accuracy of liver biopsy to assess fibrosis has also been questioned in relation to sampling errors and intra-and inter-observer variability that may lead to over-or under-staging [7][8][9][10]. Finally, liver biopsy does not allow dynamic evaluation of liver fibrosis over time.…”

Asian-Pacific Association for the Study of the Liver (APASL) consensus guidelines on invasive and non-invasive assessment of hepatic fibrosis: a 2016 update

“…It does not hinder other necessary diagnostic evaluations, and collagenous structures irrelevant to the disease process (which contribute to the variability between samples) can be excluded [56]. Considering any scoring system, the experience of the histopathologist is an important variable that must be considered and optimized [57].…”