Screening for Hepatitis B and Measles Immunity
For hepatitis B immunity screening, order anti-HBs (antibody to hepatitis B surface antigen) alone, and for measles immunity screening, order measles IgG antibody by any standard enzyme immunoassay (EIA). 1
Hepatitis B Immunity Testing
Order anti-HBs as the single test to assess hepatitis B immunity in patients with no known history of infection or vaccination. 2
Rationale for Anti-HBs Testing
- Anti-HBs identifies persons who are immune to hepatitis B, either from prior vaccination or past infection. 2
- The most efficient and cost-effective screening approach for hepatitis B immunity is testing for HBsAg and anti-HBs together, but when specifically assessing immunity (not infection), anti-HBs alone is sufficient. 2
- A protective anti-HBs level is ≥10 mIU/mL. 3, 4
Important Caveat
- If the patient has risk factors for hepatitis B exposure (persons from endemic countries, HIV-positive persons, injection drug users, men who have sex with men, hemodialysis patients), consider comprehensive testing with HBsAg, anti-HBs, and anti-HBc to distinguish between immunity, chronic infection, and susceptibility. 5
- Testing for anti-HBc alone is NOT recommended as the only screening test for immunity, though it can distinguish vaccine-induced immunity from natural immunity when needed. 2
Special Population Considerations
- For healthcare personnel with documented prior vaccination, institutions may measure anti-HBs upon hire, and those with anti-HBs <10 mIU/mL should receive additional vaccine doses. 5
- Routine postvaccination serologic testing is not necessary after standard infant, child, or adult vaccination unless the person's clinical management depends on knowing their immune status. 5
Measles Immunity Testing
Order measles IgG antibody using any standard, licensed enzyme immunoassay (EIA) to assess measles immunity. 1
Interpretation Guidelines
- Any antibody level above the standard positive cutoff value of a licensed assay is considered acceptable evidence of immunity. 1
- Positive measles IgG antibody detected by any standard serologic test constitutes evidence of immunity. 1
Critical Pitfall to Avoid
- Persons with "equivocal" serologic test results should be considered susceptible to measles unless they have other evidence of immunity. 1
- For healthcare personnel with documented MMR vaccination who test negative or equivocal, the documented age-appropriate vaccination supersedes the serologic results—they should still be considered immune. 1
Alternative to Serologic Testing
- Written documentation of 2 doses of live measles or MMR vaccine administered at least 28 days apart is alternative evidence of immunity and may be more practical than serologic testing. 1
- Do not order titers for persons with documented age-appropriate vaccination unless the medical facility considers it cost-effective. 1