Use of immunoglobulin M antibody to hepatitis B core antigen in diagnosis of viral hepatitis.

To determine the diagnostic value of hepatitis B core (HBc)-specific immunoglobulin M (IgM) antibody (anti-HBc IgM), the sera of six patients with known recent acute viral hepatitis B were examined for the presence of anti-HBc periodically for up to 21 months from the onset of the attack by a sensitive radioimmunoassay technique (CORAB, Abbott Laboratories). It was found that anti-HBc IgM was detectable for approximately 17 months from the onset of the illness. Hence the finding of anti-HBc IgM suggests infection by hepatitis B virus, probably within the preceding 1 to 2 years. A high level of anti-HBc IgM in the acute-phase serum of an individual with viral hepatitis is indicative of recent hepatitis B virus etiology; one patient, however, showed a low titer of anti-HBc IgM in the acute-phase serum sample, which remained virtually unchanged 15 months from onset. The diagnostic use of this serologaical marker is illustrated in 25 patients with viral hepatitis, in whose acute-phase sera anti-HBc was found.