Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1376 page)

   
Normal range:
Negative.

   Use

   Diagnosis of concurrent HDV infection in patients with fulminant acute HBV infection (acute coinfection), chronic HBV infection (chronic coinfection), or acute exacerbation of known chronic HBV infection (HDV superinfection).

   Interpretation

   Increased in previous or current hepatitis D infection.

   Limitations

   The role of HDV antibody testing is controversial because the incidence of infection with HDV has declined markedly in the United States with use of HBV vaccine.

   Interferon treatment may decrease the antibody levels.

   This testing should be ordered only when the patient has an acute or chronic hepatitis B infection.

HEPATITIS E VIRUS (HEV) ANTIBODY (IgM AND IgG)

   Definition

   HEV is a small nonenveloped virus that causes an acute, usually self-limited, infection that is spread by the fecal–oral route. HEV is endemic in Southeast and Central Asia, with several outbreaks observed in the Middle East, northern and western parts of Africa, and Mexico. In developed countries, HEV infection occurs mainly in persons who have traveled to disease endemic areas.

   Transmission of HEV may also occur parenterally. Direct person-to-person transmission is rare. Unusually high mortality (approximately 20%) occurs in patients infected in the third trimester of pregnancy. There is no carrier state associated with HEV.

   Viremia and virus shedding occur in the preicteric phase and last up to 10 days into the clinical phase. After an incubation period ranging from 15 to 60 days, HEV-infected patients develop symptoms of hepatitis with appearance of anti-HEV IgM antibody in serum, followed by detectable anti-HEV IgG antibody within a few days. Anti-HEV IgM remains positive for up to 6 months after onset of symptoms, whereas anti-HEV IgG levels usually persist for years after infection. Anti-HEV IgG is the serologic marker of choice for diagnosis of past HEV infection.