Does Elon Musk have the coronavirus? After four tests, he still doesn’t know.

Elon Musk, the chief executive of SpaceX, has tested positive twice, and negative twice, for the coronavirus after passing four rapid viral tests, he revealed in a report. unhappy tweet early Friday morning. The announcement came just days before his company’s highly anticipated launch of a Crew Dragon capsule that will carry four astronauts to the International Space Station.

Antigen tests, which look for chunks of coronavirus protein, are cheap and convenient, usually getting results to people within minutes. But they’re also less reliable than lab tests that use a technique called polymerase chain reaction, or PCR, which looks for fragments of genetic material. PCR-based tests are widely regarded as the gold standard in infectious disease diagnostics.

The Veritor, a product made by medical device maker BD, is advertised as having a false negative rate of 16%, making it very possible that the two negatives Mr. Musk received may have mistakenly missed the virus in his body. . But antigen tests are also prone to false positive results, which mistakenly identify healthy people as infected.

The conundrum of Mr. Musk’s testing comes at a potentially very risky time. If he was truly infected, NASA might not allow him to visit the four astronauts on Sunday, as he did with Robert Behnken and Douglas Hurley before their successful launch in May.

Shortly after tweeting his frustration at his quartet of antigen test results, Mr Musk told his supporters he had sought a follow-up PCR based test, which would provide a response within 24 hours.

Hours later, Mr Musk, who has repeatedly expressed his frustration with the pandemic and its economic fallout, took to Twitter again to question the validity of the PCR-based tests, asking his followers to tell him if the diagnostic tools were likely to generate false positives.

Mr Musk’s announcement of his testing, which was imbued with a similar note of skepticism, was greeted with a mixture of encouragement and taunt. Some people have baselessly argued that its mixed results were proof that recent increases in coronavirus cases had been inflated. Others pointed out that his repetitive testing struck a dissonant tone against the backdrop of a nation in which many still struggle to access coronavirus diagnoses.