Antibody tests check whether someone has had Covid-19 in the past. Those tests are different from tests which check to see whether someone currently has Covid-1

Antibody tests check whether someone has had Covid-19 in the past. Those tests are different from tests which check to see whether someone currently has Covid-19. If someone dies without having already tested positive for Covid-19, in many places they won't be counted as having died from Covid-19. So it's likely that many Covid-19 deaths haven't been counted - especially in places where most people can't afford the tests that check whether they currently have Covid-19.