Editing Wilson's disease (section)

===Liver biopsy===
Once other investigations have indicated Wilson's disease, the ideal test is the removal of a small amount of liver tissue through a liver biopsy. This is assessed microscopically for the degree of [[steatosis]] and cirrhosis, and [[histochemistry]] and quantification of copper are used to measure the severity of the copper accumulation. A level of 250&nbsp;[[microgram|μg]] of copper per gram of dried liver tissue confirms Wilson's disease. Occasionally, lower levels of copper are found; in that case, the combination of the biopsy findings with all other tests could still lead to a formal diagnosis of Wilson's.<ref name=Ala/>

In the earlier stages of the disease, the biopsy typically shows steatosis (deposition of fatty material), increased [[glycogen]] in the [[Cell nucleus|nucleus]], and areas of [[necrosis]] (cell death). In more advanced disease, the changes observed are quite similar to those seen in autoimmune hepatitis, such as infiltration by [[inflammation|inflammatory]] cells, piecemeal necrosis, and fibrosis (scar tissue). In advanced disease, finally, cirrhosis is the main finding. In acute liver failure, degeneration of the liver cells and collapse of the liver tissue architecture is seen, typically on a background of cirrhotic changes. Histochemical methods for detecting copper are inconsistent and unreliable, and taken alone are regarded as insufficient to establish a diagnosis.<ref name=Roberts2003/>