positive and negative covid-19 coronavirus sars-cov-2 rapid antigen test done by a nasal swab held by a medical personnel

positive negative sars-cov-2 rapid antigen test nasal swab held medical personnel covid-19 coronavirus isolated blurred background analyzing antigen cassette contagion contagious contamination corona coronavirus global crisis covid-19 diagnosis diagnostic disease epidemic equipment health hospital test hubei illustrative infection isolated lab laboratory medical negative outbreak pandemic patient patient tested pneumonia positive rapid result sample sars ag selective focus specimen swab kit viral virus virus spread