Testing has taken on new urgency in the war against COVID-19 as elected officials from mayors to governors to the president try to decide how to keep up the fight while getting Americans back to work. But there are different tests and different populations that need to be tested depending on what the goal is. Even simple questions lead to a lot of confusion. WNYC reporters Gwynne Hogan and Fred Mogul spoke to All Things Considered host Jami Floyd to clear things up.