What Does a Negative Hepatitis B Core IgM Antibody Mean?
A negative hepatitis B core IgM antibody (IgM anti-HBc) means you do not have acute or recently acquired hepatitis B infection. 1
Primary Interpretation
A negative IgM anti-HBc result excludes acute hepatitis B infection because this antibody appears at symptom onset in acute HBV infection and persists for approximately 6 months during acute disease. 1, 2 IgM anti-HBc is the most reliable marker for distinguishing acute from chronic HBV infection, so its absence rules out recent infection. 3, 2
What Your Status Could Be
Depending on your other hepatitis B test results, a negative IgM anti-HBc indicates one of the following:
Never infected with hepatitis B - If all other HBV markers (HBsAg, total anti-HBc, anti-HBs) are also negative, you have never been exposed to hepatitis B virus and are susceptible to infection. 1
Immune from vaccination - If anti-HBs is positive but total anti-HBc is negative, you have immunity from hepatitis B vaccination without prior natural infection. 1, 4
Chronic hepatitis B infection - If HBsAg is positive and total anti-HBc is positive (but IgM anti-HBc is negative), you have chronic hepatitis B infection, not acute infection. 1, 3, 2
Past resolved infection - If HBsAg is negative, anti-HBs is positive, and total anti-HBc is positive (but IgM anti-HBc is negative), you recovered from past hepatitis B infection and now have immunity. 1, 3
Critical Clinical Context
Testing for IgM anti-HBc should be limited to persons with clinical evidence of acute hepatitis or an epidemiologic link to a person with HBV infection because false-positive results can occur in asymptomatic persons. 3, 2 If you are asymptomatic and had this test performed, the negative result is reassuring but may not have been clinically necessary. 3
Important Caveat for Immunocompromised Patients
In rare cases (approximately 1.85% of HBV-infected patients), immunocompromised individuals can have active HBV replication with detectable HBV-DNA despite negative anti-HBc antibodies. 5 This occurs most commonly in patients with HIV coinfection, malignancy, or solid organ transplantation. 5 If you are immunocompromised, do not rely solely on a single negative anti-HBc result to exclude HBV infection—repeat testing with different methods or measure HBV-DNA directly may be warranted. 5
Next Steps
To fully understand your hepatitis B status, you need to know your complete serologic profile including HBsAg, total anti-HBc, and anti-HBs results. 1, 4, 3 The combination of all these markers determines whether you need vaccination, are immune, have chronic infection requiring monitoring, or have no exposure to hepatitis B. 1, 4