The nation’s top health officials are banking on a new approach to dramatically boost U.S. screening for the coronavirus: combining test samples in batches instead of running them one by one. Matthew Perrone writes for AP that the potential benefits include stretching laboratory supplies, reducing costs and expanding testing to millions more Americans who may unknowingly be spreading the virus. Health officials think infected people who aren’t showing symptoms are largely responsible for the rising number of cases across more than half of states.