Bolsonaro told CNN Brazil that he underwent an X-ray of his lungs at a military hospital as a precaution, and that the virus test results would come on Tuesday.
AFP contacted Bolsonaro's office for a comment, but his aides did not immediately respond.
Since the beginning of the virus outbreak, Bolsonaro has minimised the risks of what he initially called "a little flu" and flouted social distancing rules and containment measures, such as wearing a mask in public.
Brazil is the second worst-hit country in the world by the pandemic, with more than 65,000 deaths and more than 1.6 million cases.
On Monday, the far-right leader made more changes to weaken a law requiring that face masks be worn in public places in order to slow the spread of the coronavirus.
He had already watered down the bill Friday by vetoing several articles, including ones requiring employers to supply face masks for their staff and another mandating that public authorities should provide face coverings for "economically vulnerable people."
Now he has also vetoed articles requiring masks be worn in prisons and another obliging businesses to provide information on how to wear masks properly.