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. 2021 Jun 1;113(3):194–202. doi: 10.32074/1591-951X-242

Table II.

Brunt system to grade NASH activity (from Brunt et al., 1999) 33.

Grade Steatosis Ballooning Inflammation
Grade 1 (mild) 1-3 (up to 66%) Minimal Lobular: 1-2
Portal: none/mild
Grade 2 (moderate) 2-3 (> 33% up to 66%) Present Lobular: 2
Portal: mild-moderate
Grade 3 (severe) 2-3 Marked Lobular: 3
Portal: mild-moderate

Steatosis: grade 1 ≤ 33%; grade 2 > 33%, < 66%; grade 3 ≥ 66%.

Inflammation: Lobular (0-3): 0 (none), 1 (< 2 foci/20x field), 2 (2-4 foci/20x field); 3 (> 4 foci/20x field); Portal (0-3): 0 (none), 1 (mild), 2 (moderate), 3 (marked).