A blood test can show whether you have antibodies to the COVID-19 virus within days to weeks of having the infection or the vaccine. But antibody testing, also called serology testing, is not done routinely. A healthcare professional might use an antibody test to diagnose complications of COVID-19.

In the last few years, some at-home COVID-19 antibody tests have become available for purchase. For an at-home test, you take your own blood sample using a finger prick, and then you mail it to a lab.

A: A positive antibody test result could mean you previously had a SARS-CoV-2 infection or COVID-19. A positive antibody test could also mean the test is detecting antibodies in your blood in response to your COVID-19 vaccine. Not all SARS-CoV-2 antibody tests will detect antibodies in response to a COVID-19 vaccine.

Please note: A numerical value will be reported up to 2,500 U/mL. For patients testing higher then 2,500 U/mL, your results will be reported as “Greater Than 2,500 U/mL." Negative: You tested negative for COVID-19 IgG antibody. This means you have not been infected with COVID-19.