CDC Says Don’t Rely on Antibody Tests for Reopening Schools and Businesses The tests, also known as br serologic tests, have been br producing inconsistent br and inaccurate results. CDC, via guidance Since “overall prevalence of antibodies br in most populations is likely low,” the br tests could produce false positives br “less than half” of the time. The agency has warned those who have tested br positive for the antibodies not to assume that br they are protected from COVID-19. The CDC’s guidance follows an American br Medical Association report saying tests should br not be used in "determining immune status.