What Does a Reactive Hepatitis B Core Antibody (Total) Mean?
A reactive (positive) total hepatitis B core antibody (anti-HBc) test indicates that you have been infected with hepatitis B virus at some point in your life—either currently infected or previously infected—but this test alone cannot distinguish between acute, chronic, or resolved infection. 1, 2, 3
Understanding the Test Result
Total anti-HBc includes both IgM and IgG antibodies to the hepatitis B core antigen and appears during acute infection, typically persisting for life regardless of whether the infection resolves or becomes chronic. 1, 2
This antibody is considered the most sensitive serological marker for history of HBV infection. 4
The presence of total anti-HBc alone might indicate acute infection, resolved infection, chronic infection, or in rare cases a false-positive result. 1
Additional Testing Required for Complete Interpretation
You must obtain additional serologic markers to determine your exact HBV status—specifically HBsAg (hepatitis B surface antigen), anti-HBs (antibody to surface antigen), and IgM anti-HBc. 1, 2, 3
Interpretation Based on Complete Panel:
HBsAg positive + Total anti-HBc positive + IgM anti-HBc positive = Acute hepatitis B infection 1, 2, 3
HBsAg positive + Total anti-HBc positive + IgM anti-HBc negative = Chronic hepatitis B infection 1, 2, 3
HBsAg negative + Total anti-HBc positive + Anti-HBs positive = Resolved past infection with immunity 1, 2, 3
HBsAg negative + Total anti-HBc positive + Anti-HBs negative = "Isolated anti-HBc" pattern, which can represent resolved infection with waning anti-HBs, occult chronic infection, or false-positive reaction 3, 4
Clinical Significance of Isolated Anti-HBc Pattern
Isolated anti-HBc positivity (without HBsAg or anti-HBs) occurs in approximately 14-19% of certain populations and warrants further investigation. 5, 6
This pattern can represent occult HBV infection, with studies showing that 14.4% of isolated anti-HBc positive individuals may have detectable HBV DNA. 6
Persons positive only for anti-HBc are generally not infectious except under unusual circumstances involving direct percutaneous exposure to substantial quantities of virus. 3
Critical Clinical Considerations
If you are anti-HBc positive and will undergo immunosuppressive therapy or chemotherapy, you face risk of HBV reactivation and require serum HBV DNA testing before starting treatment. 1, 3
The CDC recommends universal screening with both HBsAg and anti-HBc testing in all patients with cancer prior to systemic anticancer therapy to prevent potentially devastating HBV reactivation. 1
Patients with chronic HBV infection (HBsAg positive pattern) require referral to a provider experienced in managing such infections, as therapeutic agents can achieve sustained suppression of HBV replication. 1
Distinguishing from Vaccination
An individual vaccinated for HBV typically has: HBsAg negative, anti-HBs positive, and anti-HBc negative. 3
Detection of anti-HBs in the absence of anti-HBc distinguishes vaccine-derived immunity from immunity acquired by natural infection (in which both anti-HBs and anti-HBc are present). 1
Common Pitfalls to Avoid
Do not assume immunity based solely on a positive anti-HBc result—you must check anti-HBs levels to confirm protective immunity. 2, 3
False-positive anti-HBc results can occur in rare cases, such as after administration of intravenous immunoglobulin, warranting clinical assessment. 1
IgM anti-HBc testing should be limited to persons with clinical evidence of acute hepatitis due to low positive predictive value in asymptomatic persons. 3