Nearly six months after COVID-19 began ravaging long-term care facilities, nursing homes across Minnesota are slated to receive new testing equipment from the federal government that should help them detect cases of the virus more rapidly.

More than 300 nursing homes statewide are expected to receive machines by the end of September that are designed to detect COVID-19 within minutes, rather than days. The devices, also known as point-of-care tests, should help nursing homes move more quickly to treat infected residents and staff, as well as isolate them sooner before they spread the virus to others.

Across Minnesota, nursing home administrators said they hope the new devices will help them ramp up testing at a time when a resurgence of coronavirus cases has placed new strains on an already stretched testing system.

Testing results have been delayed by a shortage of vital medical supplies and backlogs at the laboratories that process thousands of tests each day. In recent weeks, some long-term care facilities in Minnesota have reported delays of three to six days for COVID-19 testing results, which hinders their ability to isolate infected residents and warn people before they infect others.

The new tests dramatically reduce turnaround times for results because they can be processed on site. Currently, nursing homes that test for the coronavirus take samples from deep inside a person's nasal cavity and send them away to distant laboratories, which can take days to determine if someone is infected.

In contrast, the new tests, known as rapid antigen tests, can quickly detect certain proteins that are part of the virus and produce results within minutes, enabling nursing homes to isolate infected patients sooner and alleviate pressure on testing laboratories, federal officials maintain.

The new tests do have a significant drawback: They are less accurate than the standard tests use, known as polymerase chain reaction, or PCR.

The rapid antigen tests have been found to produce "false negative" results for up to 15% of infected people. The high error rate has caused some infectious disease experts to question the usefulness of the test for broad screening of residents and staff. Even the test's own manufacturers have cautioned that the test should only be used with people with symptoms, which limits its effectiveness given that many people with COVID-19 never show symptoms, according to a report in Kaiser Health News. The U.S. Centers for Disease Control and Prevention recently recommended that a negative result from an antigen test be confirmed by a laboratory test for those who have symptoms.

In a statement, the Minnesota Department of Health said the new testing devices could be a "useful tool" but warned of their limitations. Because such a high percentage of the tests produce false negatives, the state recommends the devices be used primarily to test symptomatic people in settings with outbreaks of the virus. In addition, the agency said, completing the test for entire resident populations could be prohibitively time-consuming. With one of the new machines, it can take 50 hours to complete 200 tests, the agency said.

Even so, long-term care industry leaders say the rapid antigen tests could help nursing homes quickly identify and contain outbreaks.

"The test is a necessary tool in the tool kit," said Patti Cullen, president and CEO of Care Providers of Minnesota, a long-term care industry group. "If the machines are out there, and you have someone who is symptomatic [with COVID-19], then use the test. Get it done right away and you will know if this person is positive."

The Trump administration announced the effort to supply nursing homes with the point-of-care testing devices in mid-July, prioritizing shipments to geographic areas that were considered hot spots for the coronavirus. About 14,000 nursing homes across the country are expected to receive the equipment for the tests by the end of September, according to federal health regulators. Assisted-living facilities will not be receiving the testing devices, because the facilities are not regulated by the federal government.

Even as they have encouraged more testing in senior homes, Minnesota Department of Health officials have repeatedly warned of the limitations of such tests. They are an important tool in identifying and isolating those who are infected, they maintain, but they should be done in conjunction with more preventive measures, such as wearing masks, physical distancing, regular hand washing and not allowing people with symptoms to go to work.

But as the coronavirus continues to spread, and national shortages of testing supplies persist, the nursing home industry and others have begun to embrace rapid and frequent testing of residents and staff as the best way to prevent outbreaks, even if the tests may be less accurate than those processed in laboratories. Even an accurate test can be rendered useless if the results do not come back soon enough, industry officials point out.

"Any reliable testing platform that can yield near immediate test results will be a powerful tool in the midst of the community spread that we are seeing — and looking ahead to the potential for more visitors in our settings," said Gayle Kvenvold, president and CEO of LeadingAge Minnesota, a long-term care industry group.

The respiratory illness caused by the coronavirus is known to be especially lethal to older adults and those living in nursing homes and assisted-living facilities, where people live in close quarters and workers move from room to room. In Minnesota, as in much of the country, these long-term care facilities remain the epicenter of the pandemic. So far, 74% of the state's 1,779 coronavirus-related deaths have been residents of nursing homes and assisted-living facilities, state health records show.

Annette Greely, chief executive of Jones-Harrison Residence, a nursing home in south Minneapolis, said that even a 48-hour wait for results, which is typical for standard lab tests, can be too long. Over that time, an infected employee or resident can unknowingly spread the virus to others in a facility and delay getting crucial treatments.

"Time does matter," Greely said. "The hope is that you would have the ability to test and know within an hour if someone has [COVID-19], and then you can start treating that person right away. You can handle the situation much more rapidly."

Twitter: @chrisserres