Hepatitis A Antibody, IgM – 006734

Hepatitis A virus (HAV) is a picornavirus primarily transmitted via the fecal-oral route. HAV replicates in the liver and is shed in high concentrations in feces from 2-3 weeks before to 1 week after the onset of clinical illness. IgM antibody typically becomes detectable within 5-10 days of the onset of symptoms, usually peaks within 1 month of illness, and decreases to undetectable levels within 6 months of infection. Many cases of HAV are subclinical, particularly in children. Antibody produced in response to HAV infection persists for life and confers protection against reinfection. The presence of IgM antibody to HAV is diagnostic of acute HAV infection. A positive test for total anti-HAV indicates immunity to HAV infection but does not differentiate active from resolved HAV infection. Although usually not sensitive enough to detect the low level of protective antibody after vaccination, anti-HAV tests also might be positive after hepatitis A vaccination.