Unclear (Isolated Anti-HBc)

For the interpretation of hepatitis B serologic test results, refer to this Table by the Centers for Disease Control and Prevention (CDC).

In cases of isolated anti-HBc positivity (HBsAg neg, anti-HBc pos, anti-HBs <10 IU/L), there are 4 diagnostic possibilities:

  1. Resolved infection (with waning anti-HBs levels many years after recovery)

Since a remote resolved infection is the most common cause of isolated anti-HBc positivity, we usually do not order any further testing. Even with negative anti-HBs levels in these cases, we do not recommend hepatitis B immunization in refugee patients because they have likely already been exposed to the virus and will not respond to vaccination.

  1. False-positive anti-HBc (susceptible)

This happens mainly in low-risk patients, which is rarely the case with refugee patients.

  1. Occult hepatitis B infection with undetectable HBsAg

Since occult infections are quite rare, we do not recommend routinely ordering HBV DNA levels to rule it out. However, since these occult infections can still lead to liver disease and hepatocellular carcinoma, they should be ruled out in patients who have concomitant HIV or hepatitis C infections, develop signs or symptoms suggestive of liver disease (e.g. elevated AST/ALT levels) or might be immunosuppressed in the future.

  1. Resolving acute infection

This should be suspected if the patient had recent symptoms suggestive of acute hepatitis. Anti-HBc IgM levels can help rule out a recent infection.

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