ROCHESTER, Minn. — Mayo Clinic Laboratories says it plans to release their long-awaited coronavirus serology test on Monday, April 6

That's one month from the first confirmed case of coronavirus in the state, and the result of a nonstop initiative within the clinic's commercial laboratory enterprise to procure a test capable of determining whether a person has been exposed to the coronavirus.

While it's not definitive without further research, experts believe it may prove likely that having contracted coronavirus will make it unlikely a person can get it again, at least in the same season.

A genuine game-changer in an outbreak that has been a lesson in the limits of modern medical technology in the face of a novel zoonotic virus, the advancement holds the hope of not only informing patients if they can safely return to crowded settings, but telling health officials whether a large enough portion of the population has contracted the virus to have loosened the need for social distancing and stay-at-home orders.

"Please tell them thank you," Gov. Tim Walz said of the news during his regular afternoon news conference on Thursday, April 2. "I watched Dr. Birx (of the White House Coronavirus Task Force) somewhat downplay this technology and I think that's a mistake. I think we would be very interested in partnering in the use of this test."

While numerous laboratory companies have released an antibody test in the past few weeks, a concern exists that tests may have emerged too quickly to have been rigorously validated, potentially offering patients false assurance they have been exposed to the virus. The FDA has yet to produce the two antibody tests they had set out to produce.

"They're very careful to make sure they know for sure what the serology is telling them," said State Health Commissioner Jan Malcolm of the Mayo Clinic Laboratories assay. "It's very promising news."

"I think from a clinical lab perspective we put our tests through a really rigorous evaluation to make sure we're getting accurate results before we offer these for clinical use," said Dr. Elitza Theel, associate professor of laboratory medicine at Mayo Clinic. "One of the biggest concerns is reporting false negatives or false positives."

MCL had already implemented a test to diagnose the virus and has put that technology to great use, clearing the backlog of tests at the state health department and going on to test five to six times the number of patients each day than is possible under the shortages of testing materials facing the Minnesota Department of Health.

Yet where the diagnostic test utilizes a throat swab — swabs now in short supply — the serology test is a standard blood draw, one which requires only three hours.

"We hope to have rapid turnaround time once it hits our lab," Theel said, "hopefully offering 12-24 hours from the test until we can deliver results."

Serology assays can post false negatives if given too early, however, as it takes seven to 10 days for the body to develop antibodies to a new virus.

"That is a big concern," Theel said. "There's a lot of these assays being offered by companies as point-of-care tests. ... For people that are presenting to a health care provider with one to three days of symptoms, chances are these tests are going to be negative. So they should not be used in acutely symptomatic patients."

One of the most transformational uses for the test would be as part of a so-called serosurvey, public health studies taken from representative samples of the population to determine if society has developed a critical mass of immunity, allowing a return to normalcy for all except those who have special vulnerabilities.

"There's definitely a lot of interest in serosurveys," said Theel. "We're going to see where that goes, and we'd be happy to help in any way we can."

Although hopes may be high, the coronavirus immunity test will not be dropped into the marketplace with the impact of a new iPhone. Theel said the number of tests now available is not yet in the thousands.

"We're doing a slow roll-out at this point, because of limited test availability. For the moment it will be open to Mayo Clinic enterprise sites. We hope to open it up to our Mayo Clinic Laboratory clients sometime in April."

Theel said the project involved a steady run of late nights and weekends.

"It's been a huge team effort, from the technologists in our lab, to people trying to get us the supplies that we need, and having people help get samples."

"One of the biggest challenges was getting serum samples from patients known to be COVID-19 positive, but at least 7-10 days after symptom onset in order to find antibodies in the blood."

"There have been a lot of challenges," she added, "but we have been able to overcome them."