Polymerase chain reaction (PCR) and rapid (antigen) tests for COVID-19 both involve taking a swab. Results for a PCR test take longer, as it needs to go to a laboratory. It is more costly but tends to ...

Abundant, free, rapid tests, many experts argue, are vitally important for mitigating what we know is fast becoming an endemic virus — Covid-19. But that is easier said than done. Between supply ...

How do rapid antigen COVID-19 tests work? Why did the US government just pledge to buy 280 million of them? And is that even enough to help curb the spread of the virus? As part of President Biden’s ...

A false positive result is possible with a rapid COVID-19 test. It happens when a person does not have COVID-19 but still tests positive for the disease. People can use a rapid COVID-19 test at home ...

At-home coronavirus screening has become a way of life for many Californians, but some medical experts are now cautioning that one test may not be enough to definitively determine whether someone is ...