Hepatitis B Core Antibody (HBcAb; Total and IgM)


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Subject: Hepatitis B Core Antibody (HBcAb; Total and IgM)

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  • Hepatitis B core antibodies appear shortly after the onset of symptoms of hepatitis B infection and soon after the appearance of HBsAg and persists for life. Initially, anti-HBcAb consists almost entirely of the IgM class, followed by appearance of anti-HBc IgG, for which there is no commercial diagnostic assay. The anti-HBc total antibodies test, which detects both IgM and IgG antibodies and is the test for anti-HBc IgM antibodies, may be the only markers of a recent hepatitis B infection detectable in the “window period.” The window period begins with the clearance of HBsAg and ends with the appearance of antibodies to HBsAg.

  • Normal range: Negative.


  • Differential diagnosis of hepatitis; diagnosis of recent or past resolved hepatitis B infection.

Determination of occult hepatitis B infection in otherwise healthy HBV carriers with negative test results for HBsAg, anti-HBs Ab, anti-HBc IgM Ab, HBeAg, and antibodies to HBeAg. 


Increased In

  • HBcAb total assay: Acute, chronic, or past resolved hepatitis B infection

  • HBcAb IgM assay: Recent infection with hepatitis B virus (≤6 months)

Decreased In

  • Normal finding.


  • Not produced after hepatitis B immunization.

  • Positive anti-HBc total antibody test results should be correlated with the presence of other HBV serologic markers, elevated liver enzymes, clinical signs and symptoms, and a history of risk factors.

  • Low levels of IgM core antibodies can sometimes be present in chronic hepatitis B, particularly during flares of activity and at times of conversion from positive antigen to positive antibody.

  • Neonates (<1-month-old) with positive anti-HBc total antibody results from this assay method should be tested for anti-HBc IgM antibody to rule out possible maternal anti-HBc total antibody causing false-positive results. Repeat testing for anti-HBc total antibody within 1 month is also recommended in these neonates.