Interobserver Agreement Using Histological Scoring of the Canine Liver

Area of Science:

• Veterinary Pathology
• Histopathology
• Canine Liver Disease

Background:

• Histological grading schemes for hepatic fibrosis and necroinflammatory activity in humans have been applied to canine chronic hepatitis.
• Interobserver agreement is crucial for reliable histological scoring systems.

Purpose of the Study:

• To evaluate interobserver agreement among pathologists using a published scoring scheme for canine hepatic fibrosis and necroinflammatory activity.
• To compare fibrosis scores from serial liver sections stained with hematoxylin & eosin (H&E) and picrosirius red.

Main Methods:

• Six veterinary pathologists scored liver sections from 50 dogs with varying degrees of fibrosis and necroinflammation.
• Multiuser kappa statistics assessed interobserver agreement.
• Fibrosis scores from H&E and picrosirius red stained serial sections were compared using the Wilcoxon signed-rank test.

Main Results:

• Multiuser kappa values for fibrosis and necroinflammatory activity were 0.35 and 0.16, respectively, indicating fair and poor agreement.
• No significant difference was found in median fibrosis scores between H&E and picrosirius red stained serial sections (P = .248).

Conclusions:

• Interobserver agreement for assessing canine liver fibrosis was fair, while agreement for necroinflammatory activity was poor.
• This suboptimal agreement necessitates careful consideration by clinicians and researchers.
• Recommendations include having multiple pathologists evaluate sections to reduce variability.