Medicine Virology 5845360f Acute infection of hepatitis B virus is diagnosed by: A IgM antibody of Hbs Ag B IgM antibody of Hbc Ag C IgG antibody of Hbs Ag D IgG antibody of Hbc Ag High-Yield Explanation Ans. is 'b' IgM antibody of HBcAg (Ref. November 2001, Micro, Harrison 17/e p 1943-44,1933-34 & 16/e, p 1823-24).