All COVID-19 antibody tests look for antibodies in the blood specific to the virus. Your immune system makes antibody proteins to help fight infections. If you were exposed to COVID-19, an antibody test will show whether or not you’ve developed antibodies against COVID-19.
There are antibody tests that look for a specific antibody (such as IgG). Other antibody tests look for the presence of any type of antibody to COVID-19.
Both types of tests are used to help identify if you have been exposed to the virus.