Intra-observer and inter-observer variation in the histopathological assessment of chronic viral hepatitis

The way in which liver biopsies showing chronic hepatitis are reported is undergoing re-evaluation. A related question is how the inflammatory and fibrotic changes in these liver biopsies can be semi-quantitatively assessed so that comparisons can be made between groups of patients and the effect of treatment on disease progression studied.

We have carried out a blinded trial in which 20 cases of chronic viral hepatitis were assessed by five histopathologists, using the Knodell and Scheuer scoring systems (two of the most commonly used systems), on two separate occasions. The results were analysed using Kappa statistics, and also by seeing for how many slides the pathologists showed no significant disagreement.

While both systems produced good inter- and intra-observer variation when fibrosis was assessed the Scheuer system produced slightly higher Kappa values. The Scheuer system produced considerably better agreement when the severity of inflammation was examined. A multirater kappa analysis confirmed that both systems showed better agreement for fibrosis scores than for inflammation scores.

We conclude that, while both systems produced reasonable agreement, this was greater using the Scheuer system. When any new scoring system is being developed, the question of reproducibility needs active consideration.