Abstract:Background/Aim: Quantitative tests of liver function may be superior to conventional tests to assess the prognosis of patients with liver diseases. There are insufficient data from quantitative testing of liver function (QTLF) for patients with chronic hepatitis B and C, particularly with regard to fibrosis. Therefore, we applied a broad panel of QTLF to these patients. Methods: Three hundred and sixty-seven consecutive patients with chronic hepatitis B or C underwent liver biopsy and QTLF, which included tests for hepatic metabolism (aminopyrine breath test, galactose elimination capacity) and for hepatic perfusion (sorbitol clearance, indocyanine green clearance). QTLF values were correlated with liver histology (grading and staging for inflammation and fibrosis) and Child–Pugh classification for liver cirrhosis. Results: In patients with no and moderate fibrosis, metabolic liver function was significantly decreased, whereas hepatic perfusion remained normal. Severe fibrosis and cirrhosis showed a significant decline in all QTLFs. Hepatic inflammation only reduced metabolic liver function, irrespective of the inflammatory grade. Viral etiology and HCV genotypes did not change QTLF. Conclusions: In summary, viral damage compromises hepatic metabolism before perfusion. Therefore, tests of metabolic liver function (aminopyrine breath test, galactose elimination capacity) should be useful to search for drugs that restore liver function in viral hepatitis irrespective of the fibrosis stage.