Hepatitis Activity Index (HAI)
Calculator
When to use
Periportal +/- bridging necrosis
None
Mild piecemeal necrosis
Moderate piecemeal necrosis, involves < 50% of the circumference of most portal tracts
Marked piecemeal necrosis, involves > 50% of the circumference of most portal tracts
Moderate piecemeal necrosis plus bridging necrosis
Marked piecemeal necrosis plus bridging necrosis
Multilobular necrosis
Intralobular degeneration and focal necrosis
None
Mild: acidophilic bodies, ballooning degeneration and/or scattered foci of hepatocellular necrosis in < 1/3 of lobules or nodules
Moderate: involvement of 1/3-2/3 of lobules or nodules
Marked: involvement of > 2/3 of lobules or nodules
Portal inflammation
None
Mild: sprinkling of inflammatory cells in < 1/3 of portal tracts
Moderate: increased inflammatory cells in 1/3-2/3 of portal tracts
Marked: dense packing of inflammatory cells in > 2/3 of portal tracts
Fibrosis
None
Fibrous portal expansion
Bridging fibrosis: portal-portal or portal-central linkage
Cirrhosis
Calculation
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