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.

Ducharme is a contributor to TIME. A medical worker performs a COVID-19 test at a screening center in Saint-Denis, France, on Nov. 4, 2020. Ducharme is a contributor to TIME. If you had COVID-19 ...

Researchers often call the polymerase chain reaction test – known as the PCR test – "the gold standard" for detecting the COVID-19 virus. The test is considered highly reliable and effective, and it ...

PCR swab tests that look for viral RNA have become the gold standard for identifying infection with the SARS-CoV-2 virus, but their results aren't 100% accurate. Researchers report that testing for ...