Primary sclerosing cholangitis (PSC) is diagnosed by measuring liver enzymes and performing cholangiography. Serum alkaline phosphatase values are 3 to 10 times the upper limit of normal, and serum alanine aminotransferase and aspartate aminotransferase levels are two to three times the upper limit of normal. Serum total bilirubin levels may be normal in 60% of patients. Serum antinuclear and anti-smooth muscle antibodies are present in 20% to 50% of patients, but antimitochondrial antibodies are rarely found in PSC