Testing is once again becoming a critical weakness in the U.S.' response to the coronavirus pandemic, and experts say we may need to revive tighter standards about who can get a test.

Why it matters: Although testing has gotten a lot better over the course of the pandemic, the pandemic has gotten worse, and that means the U.S. needs to prioritize its resources — which might mean that frequent testing solely to help open businesses or schools just isn't feasible.

Where it stands: The U.S. is conducting more than 800,000 tests per day, on average — an enormous leap from the severe testing shortages the country experienced in the spring. But it's still not enough to keep up with demand.

• Getting the results of a test often takes take longer than a week, and sometimes almost two weeks, which makes them a lot less helpful. The longer it takes to identify positive cases, the more time the virus has to spread.
• “That dramatic scale up is unprecedented, but demand has also been unprecedented,” said Julie Khani, president of the American Clinical Laboratory Association.

The big picture: Two factors are driving demand for tests higher than the system can handle: the U.S.' high caseload; and precautionary testing tied to reopening.

• Reducing turnaround times will require doing fewer tests, “and that’s in some ways taking a step backward,” said Johns Hopkins’ Caitlin Rivers. But “there is a need to identify, 'Who really does need a test? And for whom should that be high quality?'”

What they’re saying: “I’m not sure we have a shortage of testing in this country, per se. I think what we have is a shortage of smart testing," the University of Minnesota’s Michael Osterholm said.

• “We have many examples of well people being tested throughout the country that are not contacts, they just want to know,” he said.
• In a white paper published earlier this year, Osterholm and his colleagues wrote that most workplace or school-based testing is a low priority.
• There also needs to be more rigor about the timing of tests for people who might have been exposed to the virus, to avoid wasteful testing.

Between the lines: That may dash the hopes of using frequent testing as a tool to resume work, travel or other elements of pre-pandemic life, at least for now.

• Even as capacity continues to grow, including through new tests coming onto the market, it's hard to imagine a world where every sports team, business and university is able to regularly test asymptomatic people indefinitely.

The other side: Given how easily people can spread the virus before they begin to feel sick, testing still needs to be available to a lot of people who aren't symptomatic or don't know for sure that they were exposed to the virus.

• “It’s a better conversation to be had about how [we can] increase resources instead of how [we can] decrease testing," said Saskia Popescu, an epidemiologist at the University of Arizona.

Supply-chain issues make it hard to scale up testing supply, though.

• Rivers and her colleagues this week called for the federal government to do an end-to-end analysis to identify bottlenecks in the testing supply chain, as part of a reset of the U.S. coronavirus response.
• “We need basically an infusion of resources for the lab side,” Popescu said. “We need not just the actual resources like reagents and swabs, but also we need people — for them to not only do the tests, but then also communicate them.”

The bottom line: Ultimately, the best way to reduce pressure on our testing infrastructure would be to reduce the number of cases, which reduces the number of people at risk of infection.

• “Testing is not a replacement for wearing a mask,” Khani said.