Emma, a biopsy is the definitive way to determine the extent of liver damage and what is really going on. For example, with my first biopsy, it was done to determine if my hep C positive was something I'd had contact with but my immune system had successfully fought, or if it were active hep C which was currently attacking my system. The 2nd one was done to ascertain if there was cirrhosis (there was, but not with the first one 14 yrs. prior.)
Some people are felt to be at risk for profuse bleeding and not good candidates for biopsy. Sometimes people receive transjugular biopsies instead of percutaneous ones. It's all on an individual basis. These days, much can be learned from MRIs and blood work, though not cirrhosis.
Perhaps Dany can tell you more.
Hugs,
Connie