Serology is the primary method for the laboratory diagnosis of hepatitis A virus (HAV) infection. IgM anti-HAV is the reliable marker of acute infection with hepatitis A virus. Virtually all patients with acute hepatitis A have detectable IgM anti-HAV.
|Timeline for Hepatitis A Virus Infection|
Laboratory testing for IgM anti-HAV is typically positive at the time of onset of symptoms (detectable 5/6 days prior to the onset of symptoms). It remains positive for 3-6 months after primary infection.
Serological Diagnosis of Hepatitis B virus Infection
|Timeline for Acute Hepatitis B Virus Infection|
HBsAg generally appears before the onset of symptoms and peaks during overt disease. In patients who successfully clear the HBV infection and do not progress to the chronic carrier stage, HBsAg typically is undetectable 4 to 6 months after infection.
HBeAg, a soluble protein that is contained in the core of the hepatitis B virus (HBV) is generally considered to be a marker of HBV replication and infectivity.
Detection of Antibody
The first antibody to appear is IgM antibody to hepatitis B core antigen (IgM anti-HBc). The presence of the IgM anti-HBc antibody is diagnostic of acute HBV infection. IgM anti-HBc is first detectable in the serum shortly before the onset of symptoms at a time generally concurrent with the onset of elevated transaminase levels.
The presence of IgG anti-HBc indicates that the patient has a history of infection with HBV. Within several weeks, the IgM anti-HBc disappears, and IgG anti-HBc is detected. IgG anti-HBc may remain present for life.
|Timeline for Chronic Hepatitis B Virus Infection|
The presence of anti-HBs is likely to be protective against repeated HBV exposure, and the anti-HBs may persist for life.
When viral replication slows and infectivity declines, the HBeAg disappears and antibodies to hepatitis B e antigen (anti-HBe) may be detected. HBeAg to anti-HBe seroconversion occurs early in patients with acute infection, before HBsAg to anti-HBs seroconversion. Anti-HBe may persist for years.