Non-invasive assessment of liver fibrosis in chronic liver diseases: Implementation in clinical practice and decisional algorithms

Table 1 METAVIR and Ishak staging systems for liver fibrosis

Description	METAVIR (F)	Ishak (S)
No fibrosis	0	0
Portal fibrosis without septa	1	1-2
Portal fibrosis with few septa	2	3
Septal fibrosis without cirrhosis	3	4
Cirrhosis	4	5-6

Portal fibrosis is a stellate enlargement of portal tracts without any bridging fibrosis on the biopsy sample. Few septa means at least one fibrous septum on the core biopsy. Theoretically, a fibrous septum is a bridge of connective tissue between two portal tracts, a portal tract and a centrolobular vein, or between two centrolobular veins. Septal fibrosis means that the liver biopsy is crossed by several septa; the transition between F2 and F3 by METAVIR or S3 and S4 by Ishak begins when there are more fibrous septa than portal tracts without septa on the biopsy. Cirrhosis means that liver tissue is mutilated by nodular fibrosis that delineates hepatocytes nodules.