| Grade | Description |
| Mild (grade 1) | Steatosis (predominantly macrovesicular) involving up to 66% of biopsy; may see occasional ballooned zone 3 hepatocytes; scattered intra-acinar polymorphonuclear cells, intra-acinar lymphocytes; no or mild portal chronic inflammation |
| Moderate (grade 2) | Steatosis of any degree; ballooning of hepatocytes (predominantly zone 3) obvious; intra-acinar polymorphonuclear cells noted, may be associated with zone 3 pericellular fibrosis; portal and intra-acinar chronic inflammation noted, mild to moderate |
| Severe (grade 3) | Panacinar steatosis; ballooning and disarray obvious, predominantly in zone 3; intra-acinar inflammation noted as scattered polymorphonuclear cells, ballooned hepatocytes, mild chronic inflammation; portal chronic inflammation mild or moderate |
| Stage* | Description |
| Fibrosis stage 1 (F1) | Zone 3 perisinusoidal fibrosis; focally or extensively present |
| Fibrosis stage 2 (F2) | Zone 3 perisinusoidal fibrosis with portal fibrosis |
| Fibrosis stage 3 (F3) | Zone 3 perisinusoidal fibrosis and portal fibrosis with bridging fibrosis |
| Fibrosis stage 4 (F4) | Cirrhosis |
