Elon Musk took to Twitter Thursday night to say that he has received mixed 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 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. Some states don’t even bother reporting the results of antigen tests in their overall case numbers, according to a survey published in September by Kaiser Health News (KHN).

Musk has been spreading doubt, confusion, and sometimes outright misinformation about the coronavirus. He’s accused doctors of inflating case numbers for financial reasons, promoted a widely discredited paper on the benefits of chloroquine, called shelter-in-place orders “fascist,” and dismissed panic associated with the pandemic as “dumb.” In March he predicated “close to zero new cases” by the end of April.

The US is currently seeing another spike in COVID-19 cases. Just a week after reporting 100,000 cases in a single day, public health officials recorded a record 160,000 new cases on Thursday, according to the New York Times. Hospitalizations for COVID-19 also set a record of 67,096 on the same day, according to the Covid Tracking Project.