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 ...

COVID-19 rapid tests are easy to take—and then toss. So most people never report their results, which leaves health officials with an incomplete picture of how much virus is circulating and where. The ...

What does it mean if a person’s rapid antigen test result comes back positive after five days of isolation due to Covid-19? According to the experts, that person is most likely still carrying a viral ...

Members of the AGM-183A Air-launched Rapid Response Weapon Instrumented Measurement Vehicle 2 test team make final preparations prior to a captive-carry test flight of the prototype hypersonic weapon ...