Hepatitis A General Clinical Tests


Test Name Method	Hepatitis A Antibody (Anti-HA, Anti-HAV, Total Anti-HA, IgG-anti-HA, IgM-anti-HA. Total (IgG + IgM) Anti-HA IRMA, IEMAIgM-anti-HA Anti-µ capture
Specimen Requirements	Serum Stable for 7 d at RT and indefinitely at 4°C or -20°
Ref. Range Conventional International Recommended Units	Negative
Chemical Interfaces In Vivo Effects	None Found
Diagnostic Information	Hepatitis A, formerly called infectious hepatitis, is a picornavirus transmitted through either oral or fecal contact that can cause either asymptomatic infection or symptomatic clinical hepatitis. Both IgG and IgM antibodies occur early in the acute infection with IgG persisting for years. Diagnosis of acute HAV infection requires positivity dor IgM-anti-HA. Afteran acute infection, IgM-anti-HA usually disappears in 3-4 mo but may persist up to 10 mo. Patients with IgG-anti-HA are protected from the virus. Hepatitis A never causes chronic infection, and acute relapses occasionally occur. When Hepatitis A vaccine becomes available and is widely used, the existing assays may not be sensitive enough to detect post-vaccination autoantibodies which appear at relatively low titers.
Remarks	A high percentage of the population has protective antibody to the Hepatitis A virus (total anti-HA) acquired from clinically unapparent infections. This is why standard immune globulin has been effective as prophylaxis for Hepatitis A exposures.

References:
Clinical Guide to Laboratory Tests, third edition.