The Centers for Medicare and Medicaid Services will for the first time require the regular testing of nursing home staff for the novel coronavirus, the agency’s administrator said Tuesday.

Until now, such testing has only been recommended by federal authorities, in part because the slow turnaround time in getting results has seriously hampered its usefulness. But employees are thought to have played a major role in inadvertently introducing the virus to nursing homes and spreading it among residents, more than 40,000 of whom have died of covid-19, the disease caused by the coronavirus, since March.

“We want to make sure each and every nursing home is doing this,” the agency’s administrator, Seema Verma, said in a telephone news conference. Fast tests are becoming available, with more than 5,500 “point-of-care” test kits already shipped out to nursing homes across the country, according to Adm. Brett Giroir, assistant secretary for health.

Verma said nursing homes also will be required to offer tests to residents when there has been a positive test result in the facility or when someone is experiencing what could be symptoms of the virus. She said the agency will not force residents to take tests.

The tightening up comes after months of criticism of the nursing home business and of state and federal health officials who oversee nursing home operations.

Making staff testing a requirement from the beginning “absolutely would have made a tremendous difference in those states that had high outbreaks,” said Charlene Harrington, a registered nurse who is a professor emeritus in the department of social and behavioral sciences at the University of California at San Francisco. She has written several papers on the response to the coronavirus in nursing homes.

“The asymptomatic staff are as high as 50 percent, so there was no way to detect them without testing, so they were passing the virus to all the vulnerable residents,” she said.

The slow turnaround time of tests up until now could have been addressed if labs had been required to make nursing homes a priority, Harrington said. “They should have been all along. If there’s a big outbreak, they should require a test of every resident. I don’t understand why they don’t say what needs to be done, and then we can figure out how to make it happen.”

Many lives, she said, could have been saved.

Verma said $2.5 billion from the Provider Relief Fund, created by the Cares Act, will be made available to help nursing homes pay for the tests, out of $5 billion in assistance that President Trump announced in July. That’s on top of $7.5 billion that has already gone to nursing homes as emergency federal aid since the virus began to spread.

Guidance on how often staff will need to be tested will be issued later this week, Verma said. It will vary depending on a few factors, including the positivity rate in the surrounding community.

The new antigen test kits are somewhat less sensitive than the lab tests, Giroir said, but they have a 15-minute turnaround time and can conduct 10 to 20 tests per hour.

Verma said nursing homes and labs will be required to report test results to health officials, including demographic information about those tested.

The Centers for Medicare and Medicaid Services has also prepared two new online training courses, one for nursing home management and one for floor staff, on such issues as infection control, dealing with visitors, mental health, proper use of personal protective equipment and “cohorting” of residents based on who has tested positive and who has not.

It is “a tailored course that features the most recent lessons learned,” Verma said.

Rear Adm. John Polowczyk, who is coordinating the federal government’s distribution of medical supplies, told the news conference that 1.5 million N95 masks will be distributed to nursing homes in need by the end of next week.

“We continue to be in a much better place,” he said.