Here’s what you need to know about testing for coronavirus

Right now, without widespread public testing, nobody knows how many Americans have COVID-19.
But the ability of private labs to develop and analyze tests to detect if someone is or isn’t infected with the novel coronavirus that causes COVID-19 is about to expand. With that, so will identification of new cases.
Up until the last few days, only public health agencies had access to the tests, which were limited in supply. But in late February the Federal Drug Administration authorized private