From the Guidelines
To determine hepatitis B immunity, a hepatitis B surface antibody (anti-HBs) test is typically ordered, with a result greater than or equal to 10 mIU/mL considered protective and indicative of immunity. This blood test measures the level of antibodies produced against the hepatitis B surface antigen, which indicates immunity either from vaccination or from recovery after a natural infection 1. Sometimes, a more comprehensive hepatitis B panel may be ordered, which includes hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc), and hepatitis B surface antibody (anti-HBs) 1. This panel helps distinguish between immunity from vaccination (positive anti-HBs only) versus immunity from past infection (positive anti-HBs and anti-HBc) 1. Key points to consider when interpreting these tests include:
- A positive anti-HBs result indicates immunity, either from vaccination or past infection 1
- A positive anti-HBc result, in the absence of anti-HBs, may indicate a past infection with waned immunity or occult hepatitis B 1
- The presence of HBsAg indicates current infection, either acute or chronic 1
- For individuals with unclear immunity status who have been vaccinated previously, a single "challenge" dose of hepatitis B vaccine followed by anti-HBs testing 1-2 months later can also assess immune memory 1. These tests are important for healthcare workers, immunocompromised patients, and others at high risk for hepatitis B exposure to confirm protection against the virus 1.
From the Research
Hepatitis B Immunity Determination
To determine hepatitis B immunity, several laboratory tests can be used, including:
- Serologic tests to detect antibodies against hepatitis B surface antigen (anti-HBs) 2
- Molecular-based methods to diagnose acute or chronic HBV infection 3
- Detection of hepatitis B virus surface antigen (HBsAg), IgM and IgG antibodies to hepatitis B virus core antigen (anti-HBcIgM and anti-HBcIgG) 4
- Quantification of antibody against HBV core protein (anti-HBc) to identify patients with undetectable levels of HBV DNA and HBsAg seroclearance 5, 6
Laboratory Tests for Hepatitis B Immunity
The following laboratory tests can be used to determine hepatitis B immunity:
- Anti-HBs test to detect protective immune marker 2
- HBsAg test to detect hepatitis B virus surface antigen 4
- Anti-HBc test to detect antibody against HBV core protein 5, 6
- HBV DNA test to detect hepatitis B virus DNA 5
Interpretation of Laboratory Results
The interpretation of laboratory results for hepatitis B immunity is crucial for accurate diagnosis and treatment. The results of these tests can be used to: