WASHINGTON (AP) — Laboratories across the U.S. are buckling under a surge of coronavirus tests, creating long processing delays that experts say are actually undercutting the pandemic response. The bottlenecks are creating problems for workers kept off the job while awaiting results, nursing homes struggling to keep the virus out and for the labs themselves, dealing with a crushing workload. That comes as cases are rising in most U.S. states, with particular hot spots developing across the South and West. Worldwide, the count of people infected with the coronavirus passed a staggering 15 million people, with some 618,000 killed by the pandemic.