Every American traveling abroad needs to take an antigen test to return to the United States. But the start of the trip is often even more cumbersome, as many other countries (nearly every one I have ...

Molecular tests are far superior to rapid antigen tests—and now you can get them for home use. Amanda Blum is a freelancer who writes about smart home technology, gardening, and food preservation.

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.