What to Order for MMR Titer Proof of Vaccination
Order serologic testing for IgG antibodies to measles, mumps, and rubella using any standard, licensed enzyme immunoassay (EIA). 1, 2, 3
Specific Test to Order
- Request: "MMR IgG antibody panel" or individual IgG antibodies for measles, mumps, and rubella 1, 2, 3
- Any antibody level above the standard positive cutoff value of a licensed assay is considered acceptable evidence of immunity 2, 3
- The demonstration of IgG antibody by any commonly used serologic assay is acceptable evidence of immunity according to the CDC 2, 3
What Constitutes Laboratory Evidence of Immunity
For Measles:
- Positive measles IgG antibody detected by any standard serologic test 3
- Any level above the positive cutoff is considered evidence of immunity 3
For Mumps:
- Demonstration of mumps IgG antibody by any commonly used serologic assay 2
- Any antibody level above the standard positive cutoff value indicates immunity 2
- Immunity is suggested by the presence of antimumps IgG-class antibodies 2
For Rubella:
- Laboratory evidence of immunity is defined as positive rubella IgG 1
- Any standard serologic test showing positive IgG is acceptable 1
Critical Caveats
Equivocal Results:
- Persons with "equivocal" serologic test results should be considered susceptible to measles unless they have other evidence of immunity (such as documented vaccination or birth before 1957) 3
- For healthcare personnel with documented MMR vaccination who test negative or equivocal, documented age-appropriate vaccination supersedes the serologic results—they should still be considered immune 1
When NOT to Order Titers:
- Do not order titers for persons with documented age-appropriate vaccination unless the medical facility considers it cost-effective 1
- Prevaccination antibody screening before MMR vaccination is not necessary for healthcare personnel without adequate presumptive evidence of immunity 1
- During outbreaks, serologic screening before vaccination is not recommended because rapid vaccination is necessary 1
Alternative Evidence of Immunity (Non-Laboratory)
If documentation exists, laboratory testing may not be necessary 1:
For Measles:
- Written documentation of 2 doses of live measles or MMR vaccine administered at least 28 days apart 1
- Birth before 1957 (with caveats for healthcare workers) 1, 3
For Mumps:
- Written documentation of 2 doses of live mumps or MMR vaccine administered at least 28 days apart 1
- Birth before 1957 1
For Rubella:
- Written documentation of 1 dose of live rubella or MMR vaccine 1
- Birth before 1957 (except women of childbearing potential) 1
Important Testing Considerations
- IgM testing is NOT appropriate for determining immunity status—IgM is only used for diagnosing acute infection 3
- Enzyme immunoassays (EIAs) are the most commonly used commercial assays, having replaced older hemagglutination inhibition tests 2
- Commercially available antibody assays do not measure functional (neutralizing) antibodies and were designed to measure naturally acquired antibodies rather than vaccine-induced antibodies 4
- There is no reliable serologic correlate of protection for mumps specifically 4
Special Populations
Healthcare Workers:
- All healthcare personnel should have presumptive evidence of immunity documented and readily available 1
- Approximately 4-10% of healthcare personnel lack measles IgG antibodies, even among those born before 1957 3
- For healthcare workers with documented vaccination who test negative/equivocal, do not give additional doses based on serology alone—consider them immune 1