Hepatitis A Virus ( HAV) is a RNA virus of Picornavirus family transmitted by fecal- oral route. Infection with HAV is self limiting though 5-10% cases may show a secondary rise in enzymes. Since symptomatic Hepatitis A virus infections are clinically indistinguishable from Hepatitis B or C virus, serological testing is an extremely important tool to achieve proper diagnosis. During the acute phase of HAV infection, IgM appears in patient’s serum in nearly all cases at the onset of symptoms, peaks within the first month of illness and persists for 3- 6 months. It declines to undetectable levels within 12 months. The most effective diagnostic determination of HAV acute infection is the detection of Anti HAV- IgM.