Antibody tests detect the presence of antibodies of the disease, and can tell if you have been infected before – even if you didn’t have symptoms.
This is vitally important, as many people who catch COVID-19 are asymptomatic, and because symptoms can be similar to those of other infections.
Testing positive means you may have acquired resistance, while testing negative offers strong (albeit not definite) evidence that you haven’t had the virus.
Knowing your status can inform your decisions and help you manage your risk of infection – and that of those around you.