Elon Musk tweeted last Thursday night that he has received confusing results after being tested for COVID-19 and is currently experiencing symptoms of a common cold. Musk says he was tested four times using a rapid antigen test: two tests came back positive and two came back negative. He’s also awaiting the results from two PCR tests but the results won’t be known for 24 hours.
Antigen tests work by detecting a small protein on the surface of the coronavirus, whereas the more accurate PCR tests look for the virus itself. Antigen tests can be conducted quickly as they don’t require a lab, and are often administered in hotspots like college campuses or elderly care facilities. “Positive results from antigen tests are highly accurate, but there is a higher chance of false negatives,” the FDA tells us, (That’s why PCR tests are ordered for confirmation.) One such antigen test from Quidel can detect the coronavirus 85 percent of the time. Musk says his antigen test came from BD.
Nevertheless, Musk, long a COVID-19 skeptic, questions the validity of the testing with just a hint of conspiracy.