What does a positive Hepatitis B (Hep B) core antibody (Ab), total, result mean?

Interpretation of a Positive Hepatitis B Core Antibody (Total) Test Result

A positive Hepatitis B core antibody (total) test result indicates past or present infection with the hepatitis B virus (HBV), but does not by itself determine whether the infection is acute, chronic, or resolved. 1

What This Result Means

• A positive total anti-HBc test indicates that the person has been infected with HBV at some point in their life 1
• This antibody appears during acute infection and typically persists for life, regardless of whether the infection resolves or becomes chronic 1
• Total anti-HBc includes both IgM and IgG antibodies to the hepatitis B core antigen 1
• The presence of total anti-HBc alone (without other markers) could indicate several possibilities:
  • Past resolved HBV infection with undetectable anti-HBs levels 1
  • Low-level chronic HBV infection with undetectable HBsAg 1
  • False positive test result 1, 2
  • "Window period" during acute infection (when HBsAg has disappeared but anti-HBs has not yet appeared) 1

Further Testing Needed

• Additional serologic markers are required to determine the complete HBV status 1:
  • HBsAg (hepatitis B surface antigen) - indicates current infection
  • Anti-HBs (antibody to hepatitis B surface antigen) - indicates immunity
  • IgM anti-HBc - indicates recent or acute infection 3
• The complete interpretation depends on the pattern of all these markers together 1

Common Interpretations Based on Complete Serologic Panel

• HBsAg positive + Total anti-HBc positive + IgM anti-HBc positive = Acute HBV infection 1
• HBsAg positive + Total anti-HBc positive + IgM anti-HBc negative = Chronic HBV infection 1
• HBsAg negative + Total anti-HBc positive + Anti-HBs positive = Resolved HBV infection with immunity 1
• HBsAg negative + Total anti-HBc positive + Anti-HBs negative = Four possibilities 1, 4:
  1. Resolved infection with waning anti-HBs levels
  2. "Window period" of acute infection
  3. False positive anti-HBc
  4. Low-level chronic infection ("occult" HBV)

Clinical Implications

• Individuals with isolated anti-HBc positivity may benefit from hepatitis B vaccination to help determine their true status 4
• An anamnestic response (rapid rise in anti-HBs after vaccination) suggests prior resolved infection 4
• Normal response to vaccination suggests the initial anti-HBc may have been a false positive 4
• Patients with chronic HBV infection require referral to a provider experienced in managing such infections 1
• Patients with evidence of past HBV infection should be monitored if they require immunosuppressive therapy due to risk of HBV reactivation 5

Special Considerations

• In dialysis patients, a positive total anti-HBc with positive anti-HBs (>10 IU/mL) indicates immunity from prior infection and no further testing is required 1
• In HIV-infected patients, HBV vaccination should be administered to those with positive total anti-HBc but negative HBsAg and anti-HBs results (and no detectable HBV DNA) 1
• False positive anti-HBc results can occur due to heterophilic antibody interference or other technical factors 2

Remember that a single positive hepatitis B core antibody test is not sufficient to determine a person's complete hepatitis B status, and additional testing is necessary for proper clinical management 1.