Medically reviewed by Kate Colby, MPH You may get a PCR test, which can show a positive result for up to three months after recovery. If you take a rapid antigen test, it may not detect COVID after ...

At-home COVID-19 tests have become commonplace for many households, but knowing when exactly to take a rapid test — or when to throw old ones out — isn't always straightforward. Here's what health ...

The best time to take an at-home COVID-19 test may be on the fourth day of having symptoms, according to a study published in the journal Clinical Infectious Diseases. Researchers looked at nearly 350 ...

When COVID first hit, waiting days for laboratory results from an ultrasensitive polymerase chain reaction (PCR) test was commonplace. Faster tests usable by anyone, anywhere, later became widely ...