If acute viral hepatitis is suspected, the following tests are done to screen for hepatitis viruses A, B, and C: IgM antibody to hepatitis A virus (IgM anti-HAV) Hepatitis B surface antigen (HBsAg) IgM antibody to hepatitis B core (IgM anti-HBc) Antibody to hepatitis C virus (anti-HCV) and hepatitis C RNA (HCV RNA) polymerase chain reaction If serologic tests for hepatitis B confirm infection and clinical manifestations are severe, antibody to HDV (anti-HDV) levels should be measured.