Redefining Fatty Liver Disease: How Updated Nomenclature Reshapes Clinical Laboratory Diagnostics

ABSTRACT The nomenclature of fatty liver disease has undergone substantial evolution, transitioning from nonalcoholic fatty liver disease to metabolic‐associated fatty liver disease, and more recently to metabolic dysfunction‐associated steatotic liver disease. This updated nomenclature has driven a fundamental transformation in laboratory diagnostic strategies. The diagnostic framework has progressively shifted from reliance on exclusionary criteria to a multidimensional, integrated approach centered on metabolic and inflammatory biomarkers. This review aims to elucidate similarities and differences among nonalcoholic fatty liver disease, metabolic‐associated fatty liver disease, and metabolic dysfunction‐associated steatotic liver disease with respect to diagnostic criteria, epidemiological profiles, underlying pathogenic mechanisms related to insulin resistance, noninvasive imaging assessment, and key laboratory indicators.