Elon Musk seems to be calling into question the accuracy of coronavirus testing after receiving mixed results from multiple tests. The accuracy of certain types of tests for the infection has been disputed. But the billionaire is adding new fuel to the fire when it comes to doubting the effectiveness of specific testing methods.

Musk, the tech mogul behind companies like Tesla and SpaceX, is no stranger to coronavirus controversies. In September, he made waves by saying that he and his children would not be getting a potential COVID-19 vaccine if it was made available. Back in July, both he and his brother questioned false-positive testing as well as death rates in the US.

Related: Tesla CEO Elon Musk Won't Take COVID-19 Vaccine When Available

The billionaire has made it personal this time, tweeting that he had been tested for coronavirus four times in a single day. Two tests, Musk said, came back negative while the other two produced positive results. Musk said the same machine, same rapid antigen test, and even the same nurse were involved in all four instances. Musk also said he had the symptoms of a typical cold, but "nothing unusual so far."

More COVID-19 Concerns From Musk

Coronavirus anti vax

The initial tweet from Musk was really just the tip of the iceberg. Since then, he's been consistently engaging in discussions on Twitter about the legitimacy of testing. In one tweet, Musk suggested that there could be a higher false-positive percentage, and noted it could be a "possible explanation for the dramatic decline in cold & flu prevalence" compared to years past.

The FDA itself has said that no test is 100 percent accurate all of the time, listing potential factors like incorrect testing procedures that may have an impact on a test's validity. The organization says antigen tests are usually highly accurate, but false positives can happen particularly in places where very few people have the virus. The FDA also said that negative tests may need to be confirmed with a molecular test.

One more key bit of information here: the FDA noted that antigen tests are more likely to miss an active COVID-19 infection compared to molecular tests. In the case of Musk, who did say that all four of the tests he took were rapid antigen tests, the FDA typically suggests that health care providers try a molecular test as well. That being said, Musk's mixed results could be reason for concern for some who already had their doubts about how accurate current coronavirus testing is.

Next: Why Does Elon Musk Always Need To Be The Center Of Attention During Crises?

Source: Twitter, FDA