Antibody tests check your blood by looking for antibodies, which may tell you if you had a past infection with the virus that causes COVID-19. Antibodies are proteins that help fight off infections and can provide protection against getting that disease again (immunity). Antibodies are disease specific.
COVID-19 antibody testing, also known as serology testing, is a blood test that’s done to find out if you’ve had a past infection with SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19). An antibody test can’t determine whether you’re currently infected with the COVID-19 virus.
An antibody test looks for antibodies that are made by your immune system in response to a threat, such as a specific virus. Antibodies can help fight infections. Antibodies can take several days or weeks to develop after you have an infection and may stay in your blood for several weeks or more after recovery. Because of this, antibody tests should not be used to diagnose COVID-19. At this time researchers do not know if the presence of antibodies means that you are immune to COVID-19 in the future.