Therapies for non-alcoholic fatty liver disease: A 2022 update

Table 1 The non-alcoholic fatty liver disease activity score reports disease activity as a composite score, with breakdown

NAS		SAF
Component	Scoring range	Component	Scoring range
Steatosis	0-3	Steatosis	0-3
Lobular Inflammation	0-3	Activity (lobular inflammation + ballooning)	0-8
Hepatocyte ballooning	0-3
Fibrosis (separate from NAS)		Fibrosis (uses the same fibrosis staging as NAS)
F0	None
F1	Perisinusoidal or periportal
F1A	Mild, zone 3, perisinusoidal
F1B	Moderate, zone 3, perisinusoidal
F1C	Portal/periportal
F2	Both perisinusoidal and portal/periportal
F3	Bridging fibrosis
F4	Cirrhosis

NAFLD: Non-alcoholic fatty liver disease; NAS: NAFLD activity score; SAF: Steatosis activity score.