Hepatitis A virus is best diagnosed by:

Ans. is 'a' i.e., IgM antibodies in serum (Ref: 19th/e, Harrison, 2004)"Detection of IgMspecific anti -HAV in the blood of an acutely infected patient confirms the diagnosis of hepatitis A." HAV is the only cultivable hepatitis virus. Diagnosis is based on IgM detection due to the early presence of these antibodies in patient serum, in fact so early that a lack of hepatitis A antibodies at the onset of clinical manifestations excludes hepatitis A.