Updated guidance from the FDA advises people to perform repeat, or serial, testing following a negative result on any at-home COVID-19 antigen test. This can reduce the risk that an infection may be missed (false negative result). It will help prevent people from unknowingly spreading COVID-19 to others. If you believe you have been exposed to COVID-19, the FDA recommends repeat testing at 48-hour intervals for a total of at least three tests, regardless of whether you have COVID-19 symptoms.