A measles titer test is a specialized blood examination that measures the concentration of specific antibodies in the bloodstream. The term “titer” refers to this measured antibody concentration, indicating the level of protection a person has against the measles virus. These antibodies are proteins produced by the immune system in response to a past measles infection or vaccination.
Why Get a Measles Titer?
Individuals may seek a measles titer test for several practical reasons, often related to documenting their immunity. One common reason is an uncertain vaccination history, such as lost records or uncertainty about past vaccination. The test can provide definitive evidence of immunity if vaccination records are unavailable.
Many employers, particularly in healthcare or education, require proof of immunity due to measles’ highly contagious nature. Colleges, universities, and military branches also often mandate immunity for enrollment.
Before international travel, especially to regions experiencing measles outbreaks, a titer test can confirm existing immunity, helping travelers prepare and protect themselves. Individuals born before 1957 are generally presumed immune due to widespread exposure. A titer test can confirm this presumed immunity or provide official documentation after vaccination or natural infection.
Interpreting Your Titer Results
Understanding the results of a measles titer test is important for assessing one’s immune status. The test typically looks for IgG antibodies, which are indicators of long-term immunity, meaning protection from past infection or vaccination. Results are generally categorized into positive, negative, or equivocal.
A “positive,” “immune,” or “reactive” result indicates that a sufficient level of measles-specific antibodies is present in the blood. This suggests the individual is likely protected from measles infection. A positive result is considered adequate laboratory evidence of immunity.
Conversely, a “negative,” “non-immune,” or “non-reactive” result means there are insufficient or no measurable antibodies. This indicates the individual is likely susceptible to measles and could contract the disease if exposed. This can occur due to lack of vaccination, being a vaccine non-responder, or waning immunity over time.
An “equivocal” or “indeterminate” result suggests that antibodies are present but not at a protective level. Such a result is unclear and typically means the individual should be considered susceptible unless other evidence of immunity exists. In these cases, retesting or vaccination may be recommended.
What to Do After Your Titer Test
After receiving measles titer test results, the recommended course of action depends on the findings. If the results are positive, indicating sufficient immunity, no further action is typically needed for protection against measles. These positive results can often be used to fulfill immunization compliance requirements for employment or educational institutions.
If the test results are negative or equivocal, it is advisable to consult with a healthcare provider. The most common recommendation in these situations is to receive the MMR (Measles, Mumps, and Rubella) vaccine. A single dose of the MMR vaccine may be sufficient, though sometimes two doses are recommended, particularly for those in high-risk groups like healthcare personnel or students.
It is important to discuss personal health history and any specific requirements with a doctor to determine the most appropriate next steps. For those who receive a vaccination after a negative or equivocal titer, a subsequent titer may be required several weeks later to confirm the development of immunity.