Blood Tests for MMR, Hepatitis B, and Varicella Immunity Assessment
For assessing immunity to MMR, Hepatitis B, and Varicella, serologic testing for IgG antibodies is the recommended approach when vaccination history is uncertain or unavailable.
MMR (Measles, Mumps, Rubella) Immunity Testing
Recommended Tests:
- Measles: Measles-specific IgG antibody test
- Mumps: Mumps-specific IgG antibody test
- Rubella: Rubella-specific IgG antibody test
Testing Methods:
- Enzyme Immunoassay (EIA) or Enzyme-Linked Immunosorbent Assay (ELISA) are the most commonly used methods 1
- Other acceptable methods include:
- Latex agglutination
- Immunofluorescence assay (IFA)
- Passive hemagglutination
- Hemolysis-in-gel
- Virus neutralization tests 1
Interpretation:
- Any antibody level above the standard positive cutoff value of the licensed assay indicates immunity 1
- Persons with "equivocal" test results should be considered susceptible unless they have other evidence of immunity 1
Hepatitis B Immunity Testing
Recommended Tests:
- Hepatitis B surface antibody (anti-HBs): To confirm immunity from vaccination or past infection
- Hepatitis B surface antigen (HBsAg): To rule out current infection 1
Testing Considerations:
- Important to test for HBsAg before vaccination, as false-positive results can occur up to 18 days after vaccination 1
- Anti-HBs level ≥10 mIU/mL indicates immunity
Varicella Immunity Testing
Recommended Test:
- Varicella-zoster virus (VZV)-specific IgG antibody test 1
Testing Methods:
- ELISA is the most commonly used method
- IFA is also acceptable 2
Practical Considerations
Multiplex Testing Options:
- Multiplex immunoassays are available that can simultaneously test for antibodies against all these viruses (MMRV) using a single blood sample 3, 4
- These assays require only 5 μl of serum and show good correlation with individual ELISAs:
- Measles (R² = 0.98)
- Mumps (R² = 0.97)
- Rubella (R² = 0.97)
- Varicella-zoster virus (R² = 0.95) 3
Testing Timing:
- If the patient has recently received antibody-containing products (like immune globulin), testing should be delayed as these can interfere with serologic test results 1
- For varicella and measles testing, wait at least 3-11 months after immune globulin administration (depending on the product and dose) 1
Special Populations:
- For healthcare workers, serologic testing is particularly important if vaccination history is uncertain 1, 2
- Younger adults (especially those born after 1970) have higher rates of seronegativity, particularly for mumps (26%) and rubella (11%) 5
Common Pitfalls to Avoid
- Do not rely on clinical diagnosis of past disease, especially for rubella, as it is unreliable 1
- Do not assume immunity based on age alone for healthcare workers, even those born before 1957 1
- Do not test immediately after vaccination for hepatitis B, as false-positive HBsAg results can occur 1
- Do not use hemagglutination-inhibition (HI) test for rubella or measles, as newer assays have greater sensitivity 1
When ordering these tests, specify IgG antibody testing (not IgM, which indicates recent infection rather than immunity) and ensure the laboratory uses FDA-approved assays for accurate results.