Tests like this have false positive rates that are significant. The test may be a useful tool when we already reasonably expect someone to test positive (showin

Tests like this have false positive rates that are significant. The test may be a useful tool when we already reasonably expect someone to test positive (showing symptoms plus contact with a known case or travel from an affected area). However, if you have no reason to believe you are infected, a false positive might easily be more likely than a true positive. And in fact, even a very modest false positive rate would still make it orders of magnitude more likely than a true positive. Consider that even if you assume the worst about the state of the virus in the US, it's probably a few thousand people. If you randomly tested every person in the US, and the test had a false positive rate of only 1%, you would have thousands of times more positive results than real cases. Someone else in this thread mentioned an existing test that might have a 40% false positive rate.