Titer tests: Everything you need to know
Whether you're welcoming home a new baby, flying to a new destination for a vacation or working around sick patients as a doctor or nurse, your immunity is your invisible armor against all the bugs and diseases lurking out there.
Checking to see how strong that armor really is under these and other circumstances is a priority to individuals, educators and employers. Titer tests are how such strength can be measured. These quick and easy blood tests reveal whether your body has enough antibodies to fend off the infections you're hoping to keep away and can also tell you if a booster is in order.
Here's what a titer test is, how one is administered and what results you can expect from taking one.
What is a titer test?
A titer test is a simple blood test that identifies whether your body has any antibodies associated with a specific disease. An antibody is a protein that's created by your body's immune system to fight bacteria and viruses. "Prior to getting a vaccine or being exposed to a viral infection, our bodies have little to no antibodies against that specific vaccine or virus," explains Cynthia Leifer, a professor of microbiology and immunology at Cornell University. But once our body has already been exposed to a virus or vaccine, "our antibody levels against it increase dramatically," she says.
Titer tests are what's used "to help you determine if you currently have immunity to certain diseases due to past infection or vaccination,” says Dr. Alison Mitzner, a New York board-certified pediatrician and the author of "Calm and Confident Parenting."
In other words, whether you’re going to be exposed to varicella (chickenpox), hepatitis, rubella, COVID-19 or the measles or mumps, these tests will help you know if you'll be protected. And for some of these diseases that provide long-term or lifelong immunity after exposure, a single titer is all that is needed to know if protection is still intact. But for viruses like COVID-19, multiple tests may be necessary as such antibody levels ebb over time.
How is titer testing given?
A titer test is administered through a standard blood draw that's both quick and usually painless. No special preparation is necessary, and the procedure takes only a few minutes. "They are administered by a healthcare provider at the doctor's office, in the hospital, at various pharmacies or at laboratory diagnostic centers,” says Mitzner.
A few days after your blood has been drawn, your healthcare provider will receive the results and contact you "to go over the results and to make recommendations for any treatments or vaccines,” says Leifer.
Who is titer testing for?
Just about anyone can get a titer test. They’re especially valuable for people who don't have a complete record of their past vaccinations, pregnant women and individuals who are frequently interacting with large groups of people. Healthcare professionals and healthcare students also usually want them because of the number of sick patients they are frequently exposed to.
Parents of a new baby, people with autoimmune disorders or symptoms "and individuals who may have been exposed to an infection while traveling abroad may want clear evidence of immunity against specific diseases or need a titer test to confirm their immune response,” says Mitzner.
Sometimes employers and school systems also recommend for an employee or a student to take a titer test, particularly if that employee or student doesn't have a complete record of past vaccinations.
What do titer test results mean?
Titer tests can show if you have active immunity that you've received directly from a past infection or vaccine; passive immunity that's been passed from mother to baby or from donated blood; or no immunity at all.
And titer tests don't just determine if you have immunity, they can also help you determine just how protected you really are; they quantify the number of specific antibodies in your blood. “Titer tests measure both the amount and type of antibodies in a blood sample," explains Leifer. “This information is used to help you determine if you should receive treatment for a viral infection you may have been exposed to or be given a vaccine or booster to protect you against one going forward."