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 ...

A polymerase chain reaction (PCR) test detects genetic material from a pathogen or abnormal cell sample. Ways of collecting samples include a nasal swab, a saliva swab, or taking a sample of blood.

COVID-19 tests are in greater demand than ever, and new data about the Omicron variant can make picking and using different types of tests confusing. Molecular tests for COVID-19, like the "RT-PCR" ...

WASHINGTON — As the omicron variant sweeps through the U.S., testing has never been more important. Early January brought a new claim to the forefront of at-home testing discourse: you should swab ...