Limitations of liver biopsy and non-invasive diagnostic tests for the diagnosis of nonalcoholic fatty liver disease/nonalcoholic steatohepatitis

Table 2 Pathological criteria for the diagnosis of nonalcoholic steatohepatitis

Criteria (yr)	Classifications	Definitions of NASH	Characteristics
Matteoni (1999)	Type 1: steatosis aloneType 2: steatosis with inflammationType 3: steatosis with hepatocyte balloningType 4: Type 3 plus MDB or fibrosis	Type 3 or 4	Depend on the subjective judgments of observers(existence of hepatocyte balloning)Well correlation with liver-related mortalityInflammation is not included
NAS (2005)	Steatosis (0-3) Inflammation (0-3) Hepatocyte balloning (0-2) Total: 0 to 8	Total scores: 5 to 8	Numerical scoreLow sensitivity, NAS ≥ 4 may be better Fibrosis is not includedNo significant correlation with liver-related mortality Recommended use for assessing the therapeutic effect during clinical studies
Younossi (2011)	SteatosisHepatocyte balloningMDBFibrosis	Steatosis + Hepatocyte balloningor + MDBor + Fibrosis	Inflammation is not includedWell correlation with Matteoni’s classificationCan diagnose so-called burned-out NASHEssential validation study

MDB: Mallory-Denk bodies; NAS: Nonalcoholic fatty liver disease activity score; NASH: Nonalcoholic steatohepatitis.