Months into the pandemic, many U.S. cities still lack testing capacity.
In the early months of the outbreak in the United States, testing posed a significant problem, as supplies fell far short and officials raced to understand how to best handle the virus. Since then, the country has vastly ramped up its testing capability, conducting nearly 15 million tests in June, about three times as many as it had in April.
But in recent weeks, as cases have surged in many states, the demand for testing has soared, surpassing capacity and creating a new testing crisis.
In many cities, officials said a combination of factors was now fueling the problem: a shortage of certain supplies, backlogs at laboratories that process the tests, and skyrocketing growth of the virus as cases climb in almost 40 states.
Fast, widely available testing is crucial to controlling the virus over the long term, experts say, particularly as the country reopens. With a virus that can spread through asymptomatic people, screening large numbers of people is seen as essential to identifying those who are carrying the virus.
Testing in the United States has not kept pace with other countries, notably in Asia, which have been more aggressive. When there was an outbreak in Wuhan in May, for instance, Chinese officials tested 6.5 million people in a matter of days.
In Arizona, where reported cases have grown to more than 100,000, a shortage of testing has alarmed local officials, who say they feel ill equipped to help residents on their own.