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You had some sniffles over the holidays. You had exposure to COVID at work. Your spouse had confirmed COVID.
Now, weeks later, you want to know if you had omicron and whether the low-level infection will offer you any immunity going forward.
The COVID tests you take at the drive-thru, walk-up and pharmacy are rapid antigen tests or PCR tests—both which diagnose a current infection.
What you need is an antibody test, which is done through a blood sample and looks for antibodies made after a COVID infection.
The test identifies antibodies in your blood, looking for two different types: One that indicates a recent COVID infection and the other that shows antibodies that could come from either a vaccine or infection.
“It’s important to know if the test you are taking looks for both types,” said Dr. Jason Lane, ChenMed’s National Medical Director, Clinical Strategy and Outcomes.
COVID-19 antibody tests are available at doctors’ offices, laboratories and drug stores. Make sure to ask which type you are getting and check the FDA website for the accuracy of that specific test. You also want to know whether the test will give you specific levels or simply a general “positive” or “negative” result.
CVS Minute Clinic offers the QuestDirect COVID-19 antibody test for $69. That test can detect antibodies from a prior or recent infection, but not the type of antibodies from a vaccine.
The tricky part is if the test is negative for antibodies, it could mean a few different things: that you haven’t been exposed to the coronavirus or the vaccine, or that your antibodies have waned to a level where the test can no longer detect them.
“Antibody tests can be helpful but they are difficult to interpret and use correctly,” Lane said. “While the test might tell you that you did have COVID and do have antibodies, it doesn’t mean you are 100% protected from getting COVID again.”
One reason to get tested is to better understand your risk. Experts say you are extremely unlikely to be reinfected with the same COVID-19 variant within a month or two of recovering.
Jake Greenfield, 25, of Fort Lauderdale, says he is going to get an antibody test to know if he needs to be as cautious with mask-wearing.
“I had a sore throat in December, and it went away in a few days. A rapid test came back negative but I still think I had omicron. If I had it, I won’t be as worried about getting it as I am now.”
Yet, the bigger question that many want to know is whether having a mild case of omicron with little to no symptoms has boosted their immunity enough to offer some protection from reinfection going forward.
No one knows that for certain. The amount of antibody protection that people get from an infection varies from person to person. The amount of antibodies each person might need for protection from a future infection also differs from person to person, which is why the FDA does not recommend the tests as a means of learning your immunity level.
Still, several commercial labs sell tests to measure levels of antibody immunity against COVID-19.
Melissa Hill, a senior research scientist at Ethos Labs in Newport, Kentucky, says her company sells a do-it-yourself fingerprick blood test that measures the percentage of antibodies that block and inhibit the virus. The test sells for $125.
Ideally, she says, you want neutralizing antibodies of greater than 80%. The test won’t differentiate whether your high level is from vaccination or infection.
“Everyone uses the information in a different way,” Hill says. “You can monitor yourself every three months or six months to determine when to get a booster. It’s just another tool in the toolbox to make informed decisions about your care.”
Cindy Krischer Goodman