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COVID-19 antibody test not necessarily an indicator of immunity

Written By: Simone Sonnier, UT Physicians | Updated: March 29, 2021
COVID-19 antibody test vial

Depending on the type of antibody test you receive, your results may be unreliable.

After becoming fully vaccinated, some individuals may want confirmation of their immunity through a COVID-19 antibody test. Experts like Luis Ostrosky, MD, infectious disease specialist with UT Physicians, agree that these tests are unnecessary and can be unreliable.

Antibody testing

The Centers for Disease Control and Prevention (CDC) does not recommend checking for antibodies after vaccination because of several different factors such as determining what level of protection is ideal and problems with the type of test administered.

Luis Ostrosky
Luis Ostrosky, MD

“Even if you have antibodies, we still aren’t sure what level or what type are best for protection purposes,” said Ostrosky, who is also a professor and division director of infectious diseases at McGovern Medical School at UTHealth.

Simply put, antibody tests are not a true measure of how protected you are from COVID-19. There are mechanisms of protection that will not show up in a test, like how your T-cells will respond when exposed to the virus.

Another issue Ostrosky brings up is the type of test administered.

“When most people sign up for a test, most laboratories and providers are typically testing for anti-nucleocapsid antibodies,” said Ostrosky. “The problem with that is those are not antibodies that would be created by the vaccine, but only through natural infection.”

If you are determined to test your immunity, Ostrosky recommends the following:

  • Wait two weeks after your final dose of the COVID-19 vaccine.
  • Seek out an anti-spike protein COVID-19 antibody test, which are the antibodies that vaccines create.
  • Understand we still don’t know the correlation between the level of antibodies you have versus your immunity to the virus.

“If you get tested for antibodies and the results come back low or with none at all, that does not mean that your vaccination didn’t work,” Ostrosky said. “You should talk to your doctor about your results.”

To learn more about the vaccine, please visit our COVID-19 Vaccine Update page.

As the clinical practice of McGovern Medical School at UTHealth Houston, UT Physicians has locations across the Greater Houston area to serve the community. To schedule an appointment, call 888-4UT-DOCS.