The findings suggest obstructive jaundice from biliary tract disease (e.g., gallstones). Elevation of the serum alkaline phosphatase level is characteristic of cholestasis from biliary obstruction. The alkaline phosphatase comes from the bile duct epithelium and hepatocyte canalicular membrane. The blood ammonia concentration increases with worsening liver failure. When hepatic failure is sufficient to cause hyperammonemia, mental obtundation is seen. In this case, the patient has only jaundice. Primary biliary cirrhosis with an increased antimitochondrial antibody titer is much less common, and PBD eventually leads to bile duct destruction. Most cases of active HCV infection are accompanied by some degree of inflammation with fibrosis. In obstructive biliary tract disease, the direct bilirubin, not the indirect bilirubin, should be elevated.