The United States might have more COVID-19 testing capacity than any other country. So why have we seen laboratories overwhelmed and many patients again waiting a week or more for results? At the heart of the crisis is a reliance by public and private labs on automated testing equipment that locks them in to using proprietary chemical kits and other tools made by a handful of manufacturers. The result: as infection rates spike nationwide, many labs aren’t running anywhere near capacity because of supply-chain bottlenecks, according to Reuters interviews with 16 hospital, state, commercial and academic labs and an analysis of state and city procurement plans.