Non-alcoholic fatty liver disease in 2015

Table 1 Brunt classification of steatohepatitis[27]

Grades of NASH
Grade 1 (mild)	Steatosis up to 66%. Occasional ballooned hepatocytes predominantly in zone 3. Scattered intra-acinar neutrophils
Grade 2 (moderate)	Steatosis of any degree. Ballooned hepatocytes predominantly in zone 3. Intra-acinar neutrophils. Zone 3 perisinusoidal fibrosis. Mild to moderate portal and intra-acinar chronic inflammation
Grade 3 (severe)	Panacinar steatosis. Widespread ballooned hepatocytes predominantly in zone 3. Intra-acinar inflammation. Scattered neutrophils associated with ballooned hepatocytes. Mild to moderate portal inflammation
Stages of NASH
Stage 1	Extensive zone 3 perisinusoidal fibrosis
Stage 2	Zone 3 perisinusoidal and portal or periportal fibrosis
Stage 3	Bridging fibrosis
Stage 4	Cirrhosis

NASH: Non-alcoholic steatohepatitis.

Table 2 Non-alcoholic steatosis or non-alcoholic fatty liver disease activity score is determined by evaluating the steatotic and inflammatory activity

NAS	Steatosis	Ballooning	Inflammation, lobular
0	< 5% (0)	None (0)	None (0)
3	5%-33% (1)	Rare or few (1)	1–2 foci per 20 × field (1)
6	34%-66% (2)	Many (2)	2–4 foci/20 × field (2)
8	> 66% (3)	Many (2)	> 4 foci/20 × field (3)

NAS: Non-alcoholic steatosis.

Table 3 Several noninvasive scoring systems based on indirect serologic markers of fibrosis are available to predict the presence or absence of advanced hepatic fibrosis

BARD (BMI > 28, AST/ALT ≥ 0.8 and diabetes mellitus) score[29]: Score ranges from 0 to 4. BMI > 28 (yes = 1, no = 0) + AST/ALT (> 0.8 = 2, ≤ 0.8 = 0) + diabetes mellitus (yes = 1, no = 0)	Score 0 to 1 means low probability of advanced hepatic fibrosis (negative predictive value 96%) and score 2 to 4 means high probability of hepatic fibrosis (positive predictive value 43%)
NAFLD fibrosis score: depends on age, BMI, diabetic status, AST, ALT, Platelet Count and albumin[30]: -1.675 + 0.037 × age (yr) + 0.094 × BMI (kg/m2) + 1.13 × IFG/diabetes (yes = 1, no = 0) + 0.99 × AST/ALT ratio - 0.013 × Platelet (109/L) - 0.66 × albumin (g/dL)	If the score is < -1.455, there is low probability of advanced hepatic fibrosis (negative predictive value ≥ 87%) and if the score is > 0.676, there is high probability of advanced hepatic fibrosis (positive predictive value ≥ 78%). If the score is intermediate (between -1.455 and 0.676), there is indeterminate probability and these patients need to have liver biopsy for further assessment
Fibrosis 4 index: Uses age, AST, ALT and platelet count[31]: Age (yr) × AST (U/L)/platelet (109/L) × [ALT (U/L)]1/2	If the score is < 1.30, there is low probability of advanced hepatic fibrosis (negative predictive value 90%), if the score is > 2.67, there is high probability of advanced hepatic fibrosis (positive predictive value 80%). If the score is intermediate (1.30 to 2.67), the possibility of having advanced hepatic fibrosis is indeterminate and liver biopsy is warranted
APRI[32]: AST level (IU/L)/AST upper limit of normal (IU/L)/[platelet count (109/L)] × 100 =	If the score is ≤ 0.5, there is low probability of hepatic fibrosis negative predictive value 83% and if the score is > 1.5, there is high probability (positive predictive value 68.4%) of hepatic fibrosis[33]. The intermediate score is indeterminate and liver biopsy should be done in those patients

BMI: Body mass index; ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; NAFLD: Non-alcoholic fatty liver disease; IFG: Impaired fasting blood glucose; APRI: AST platelet ratio index.