Recently we have shown that cartilage oligomeric matrix protein (COMP), a fibrillar collagen assembly regulator, is strongly associated with cirrhosis and hepatocellular carcinoma progression. Therefore, we assessed whether serum COMP levels can be used as a non-invasive fibrosis marker in patients with chronic viral hepatitis (CVH) and compared this marker with standard methods for disease stage assessment [histology, transient elastography (TE), APRI, FIB-4].