What Is an Antigen Test?

Understanding a new type of coronavirus test authorized by the FDA

A Sofia machine, made by Quidel Corporation, which is used to run the company’s 15-minute Covid-19 antigen test. Photo: Quidel

A new category of coronavirus tests is here. On May 9, the U.S. Food and Drug Administration authorized the first antigen test to diagnose Covid-19, made by Quidel Corporation, a San Diego-based company that develops medical testing. Former FDA commissioner Scott Gottlieb told CBS’s Face the Nation that the…