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.

PCR is a technique used to amplify target DNA in a sample. It’s a well-known method that has undergone numerous modifications to enhance its capabilities. This year, it’s turning 40 years old. PCR has ...