Tests done routinely to determine the cause include Viral hepatitis serologic tests (eg, IgM antibody to hepatitis A virus [IgM anti-HAV], hepatitis B surface antigen [HBsAg], IgM antibody to hepatitis B core antigen [IgM anti-HBcAg], antibody to hepatitis C virus [anti-HCV]) Autoimmune markers (eg, antinuclear antibodies, anti-smooth muscle antibodies, immunoglobulin levels) Other testing is done based on findings and clinical suspicion, as for the following: Recent travel to countries where sanitation is poor: Tests for hepatitis A, B, D, and E Females of child-bearing age: Pregnancy testing Age < 40, hemolytic anemia, and a pattern showing a low alkaline phosphatase level with alkaline phosphatase / total bilirubin ratio < 4 and the aspartate aminotransferase (AST) level greater than the alanine aminotransferase (ALT) level, with elevations in ALT and AST (although usually < 2000): check ceruloplasmin level for Wilson disease Suspicion of a disorder with structural abnormalities (eg, Budd-Chiari syndrome, portal vein thrombosis, liver metastases): Ultrasonography and sometimes other imaging Patients should be monitored closely for complications (eg, subtle changes in vital signs compatible with infection), and the threshold for testing should be low.