The governor said her administration has been working for weeks on the deal with Idexx and needed to wait until the company’s test kits received FDA approval. That happened Thursday morning.

“Right now, we welcome good news in any form and in any way it comes to us,” Mills said during the state’s daily briefing. “This is very good news.”

Dr. Nirav Shah, director of the Maine Center for Disease Control and Prevention, said the testing ramp-up wouldn’t happen overnight but could be in place by the end of next week.

Shah did say that with an increase in testing, it’s possible that Maine will see an increase in new cases.

“One of the things we know in public health and in life is that when you go out looking for things, you often find them,” he said. “And we want to look under every stone possible.”

The latest numbers Thursday offered a good example. Maine had 76 new cases – the largest single-day total since the outbreak first hit – but two-thirds of those cases were at Tyson Foods, a poultry processing plant in Portland, and Springbrook Hospital in Westbrook, two places where universal testing was ordered after outbreaks.

Shah said that as the state expands testing, it will look at not just the number of new cases but also the rate of positivity. Maine’s current rate of positive cases is just over 5 percent, which is relatively low. Massachusetts, by comparison, has a positive rate of 21 percent.

Mills, who has hinted in recent days that she’s considering revising her phased plan to reopen the state’s economy, also said experts can’t rely solely on new cases, which could go up. She said new hospitalizations, and spikes in deaths, will be important to monitor.

Mills praised Idexx, the Westbrook-based firm best known for animal diagnostic testing, for partnering with the state on the $725,000 contract, which will be paid with federal coronavirus relief funds.

Another firm with Maine ties, Chicago-based Abbott Laboratories, also received FDA approval last month to distribute testing kits, but the federal government purchased most of them and distributed them to other states with higher case numbers before Maine could buy any.

Mills said she wanted to avoid that dynamic this time and work to ensure Maine doesn’t become the next hot spot.

Shah explained that one of the reasons Idexx was well suited to partner with the state was because of its supply of chemicals needed to run each test. For weeks, Maine and other states have relied on the federal government for these so-called reagents, which have been in short supply.

“We’ll have independent ability to keep a steady supply of ingredients,” he said.

The deal could mean more business for Idexx, too, which has suffered during the pandemic like so many other companies.

“I am grateful to the frontline workers in Maine and around the world who have been working tirelessly to help treat and contain the spread of COVID-19,” Idexx President and CEO Jay Mazelsky said in a statement. “Assisting governments with infectious disease management is core to what we do and all of us at Idexx are proud to be able to leverage our capabilities in support of these efforts in our home state of Maine.”

The additional testing will be conducted at the Maine CDC’s Health and Environmental Testing Laboratory in Augusta, aided in part by a new testing instrument being loaned by Idexx. Once the instrument is operational, health care providers can begin requesting tests without having to worry about supply, Shah said.

The state also plans to use the new capacity to fully implement universal testing in congregate care settings, such as nursing homes, several of which have seen outbreaks, some of them deadly. Right now, the state is able to implement universal testing only after an outbreak occurs.

Additionally, the new testing volume could allow for some sentinel, or random, testing, which helps officials determine the spread of the virus in certain areas. That’s important in combating future spread of the coronavirus, which some people can have without showing any symptoms.

Shah said the CDC is in the process of hiring new employees to assist with processing tests. Most lab workers, he said, have been working seven days a week since mid-March.

“That’s not the way to do business,” he said.

Even with Thursday’s announcement, Mills said her administration would continue trying to expand testing and also to pressure the federal government to ensure health care providers have enough materials, such as swabs, to do the tests.

Public health experts say that widespread testing, a downward trend in cases for at least two weeks, and robust tracking and tracing of people who had contact with an infected person are critical components for reopening an economy without overloading the health care system with new cases.

Asked whether the new tests might be used on potential visitors to Maine, Mills said it’s possible. One of the major challenges to reopening Maine’s economy, particularly near the start of tourist season, is how to monitor visitors from other states, including those where case numbers are significantly higher. Mills’ plan currently calls for out-of-state visitors to quarantine for 14 days, a requirement that many in the hospitality industry have said is unrealistic and could cripple them economically.

Mills said she would likely announce in the coming days any changes to her plans to reopen the state slowly and safely, but she said Mainers should welcome this bit of good news.