Validating NAFLD Scoring System

To validate the scoring system, 36 slides of mouse livers covering the whole spectrum of NAFLD, were blindly analyzed by a board-certified pathologist (A.L.M), a clinical pathologist (A.D.) and nine scientists with basic histological experience. For the validation, the observers estimated the percentage of macrovesicular steatosis, microvesicular steatosis and hypertrophy (relative scale) and the number of inflammatory foci per field (absolute scale), instead of using the different categories for steatosis and inflammation (ordinal measure). Additionally, quantification of the steatosis and inflammation was determined by one observer during two separate assessments that were separated by an interval longer than 3 months.