BACKGROUND

The diagnosis of NAFLD and NASH remains one of clinicopathologic correlation.[1][2][3] In evaluation of subjects suspected to have NAFLD or NASH, standard laboratory tests may document liver test elevations and exclude a variety of potential underlying causes of liver dysfunction. Careful clinical evaluation may exclude alcohol as a significant underlying factor and radiological findings may confirm hepatic steatosis but may not be reliable with small amounts of steatosis. However, there are no tests that replace liver tissue analysis to confirm or exclude the diagnosis of steatohepatitis. Biopsy analysis is also necessary to determine the extent of active injury, the presence and character of fibrosis, and the degree of architectural remodeling. Biopsy evaluation is considered the “gold standard.” Finally, although the pathologist may document the lesions of steatohepatitis, histological evaluation often cannot reliably distinguish between alcoholic and nonalcoholic origin. Just as the clinician cannot diagnose steatohepatitis, the pathologist cannot always discern nonalcoholic origin.