Antibody Blood Tests, also known as antibody or serology tests, look for antibodies specific to SARS-CoV-2 by checking a blood sample (usually by a blood draw), which tells if you were exposed to the COVID-19 virus in the past and has developed an immune response. Only a positive antibody test can reveal that someone has been infected with the virus at some point in the past. It is also important to remember that people can have a positive antibody test and still be contagious to others if the infection occurred only a few days before testing.
Relying on the timing of the test and when someone was infected with the virus, the test may not be able to indicate and confirm antibodies in a person currently infected with COVID-19; since it can take up to three weeks or more for the body to make antibodies after a COVID-19 infection. Antibody tests should not be used as an alternative to diagnose someone as being currently sick with COVID-19.
The antibody test can also help identify if you’re eligible to donate a part of their blood called convalescent plasma, consisting of antibodies against the virus. This blood may be able to save a life who is severely ill from the virus.
A positive result tells that you most probably have antibodies against the COVID-19 virus. Nonetheless, there is still a possibility that a positive result means you have antibodies from an infection with a different virus from the same family of the viruses, coronaviruses.
Having antibodies to the virus also protects from getting the same virus again. But even if it does, we cannot tell how much defense the antibodies will provide and for how long. Also, confirmed reinfection cases had been reported.
Share your result and the type of test you took with your healthcare provider to understand better what your result means. You might have to take the second test to check the accuracy of the first test.
Since you can get infected again, you should be careful and continue to protect yourself and others.
You can also result positive for antibodies even if you never had the symptoms of the virus. This is called asymptomatic infection means; you suffered infection without symptoms.
You might be currently infected or been recently infected.
You might never have COVID-19. Discuss your result with your healthcare provider to better understand what the result means.
The test came out negative because it normally takes 1-3 weeks to develop antibodies. There’s a chance you can still get sick if you have been exposed to the virus recently, meaning you can still spread the virus.
It takes longer than 1-3 weeks to develop antibodies in rare cases, and sometimes, infected people may not be able to develop antibodies again.