"I'm sure you've heard of the troubled story of rolling out testing to the state public health laboratories," Dr. Larry Madoff of the Massachusetts Department of Public Health told lawmakers Wednesday. "I'm happy to say that we've overcome those obstacles now, and that testing is going on, has been going on since last week at the state public health laboratory."

That "troubled story" refers to widespread complaints that the supply of tests from the federal government has fallen far short of what's needed. Now, the federal criteria for testing have been broadened to allow doctors more discretion to order tests, and Madoff told lawmakers the supply is expanding.

"As the availability of tests increases — and we're expecting to bring on board today about a thousand additional tests' capacity — that will help us increase the amount of testing that we're able to do," he said.

At this point, testing is limited to people who have symptoms, he told the Legislature's Joint Committee on Public Health. Novel coronavirus symptoms include fever, cough and shortness of breath.

For health care staffers who need to diagnose patients, expanded testing can't come soon enough.

"Right now, the biggest resource constraint that we have is the ability to do widespread diagnostics," said Dr. Rochelle Walensky, the chief of infectious diseases at Massachusetts General Hospital. More diagnostic tests are needed immediately — or rather, "yesterday," she said.

Until now, only a trickle of patients at Mass. General could be tested for the novel coronavirus, Walensky said. Public health officials have reported administering only 20 coronavirus tests in the state so far, including just two patients who tested positive and are now recovering.

And if tests were abundant?

"I think we would want to test everybody with an influenza-like illness in the ER," Walensky said.

Thus far, in-house labs at Partners Healthcare, the state's largest hospital chain, cannot do their own testing, Dr. Michael Mina, an epidemiologist and clinical testing expert at Brigham and Women's Hospital and Harvard, told the legislators.

"We still don't have a single test that's operational for clinical use in any of the Partners hospitals but we will get there soon," he said. More broadly, scaling up to testing widespread enough to screen the population for the coronavirus "is going to be a real challenge," he said.

Ultimately, Walensky from Mass. General said, having many more tests could also help calm fears about the new coronavirus and its mortality rate, initially estimated at around 2%. She says it is scary that the coronavirus is likely to make many people sick.

"The reason I think it's so scary is because we don't know how many people have it who don't get that sick," she says. "That's really where the diagnostic could be super-helpful here."