Here’s what the CDC says about antibody tests:
If you test positive
A positive test result shows you may have antibodies from an infection with the virus that causes COVID-19, or possibly from infection with a related virus from the same family of viruses (called coronavirus), such as one that causes the common cold.
We do not know yet if having antibodies to the virus that causes COVID-19 can protect someone from getting infected again or, if they do, how long this protection might last.
Talk with your healthcare provider about your test result and the type of test you took to understand what your result means. Your provider may suggest you take a second type of antibody test to see if the first test was accurate.
You should continue to protect yourself and others since it’s possible you could get infected with the virus again.
If you have no symptoms, you likely do not have an active infection and no additional follow-up is needed.
If you work in a job where you wear personal protective equipment (PPE), continue wearing PPE.
If you have symptoms and meet other criteria for testing, you would need another type of test called a viral test. This test identifies the virus that causes COVID-19.
This test uses respiratory samples, such as a swab from inside your nose, to confirm COVID-19.
An antibody (blood) test cannot tell if you are currently sick with COVID-19.
You might test positive for antibodies even if you never had symptoms of COVID-19. This can happen if you had an infection without symptoms (also called an asymptomatic infection).
If you test negative
You may not have had COVID-19 before. Talk with your healthcare provider about your test result and the type of test you took to understand what your result means.
You could still have a current infection.
The test may be negative because it typically takes 1 to 3 weeks after infection to develop antibodies. It’s possible you could still get sick if you have been exposed to the virus recently. This means you could still spread the virus.
Some people may take even longer to develop antibodies, and some people may not develop antibodies.
If you have symptoms or develop symptoms after the antibody test and you meet other criteria for testing, you would need another type of test called a viral test. This test uses respiratory samples, such as a swab from inside your nose, to confirm COVID-19. An antibody (blood) test cannot tell if you are currently sick with COVID-19.
Regardless of whether you test positive or negative, the results do not confirm whether or not you are able to spread the virus that causes COVID-19. Until we know more, continue to take steps to protect yourself and others.