University of Minnesota, Mayo Clinic ramp up COVID-19 testing, putting Gov. Tim Walz's 'moon shot' goal in reach

Gov. Tim Walz's "moon shot" proposal for 5,000 daily COVID-19 diagnostic tests in Minnesota appears within reach after the University of Minnesota and Mayo Clinic unveiled aggressive in-state solutions for a global testing shortage.

While contingent on $20 million in state funding, the U on Thursday proposed ramping up its lab capacity in Minneapolis to conduct 10,000 daily molecular tests to diagnose active infections and 10,000 daily serological antibody tests to find people who have recovered.

Walz has called for more in-state testing to track the outbreak before he scales back the current stay-at-home order, which is scheduled to end May 4. The U should be ready then, said Dr. Timothy Schacker, the U medical school's vice dean for research.

"Our aim is to be up and running by that time, for sure," he said.

The two testing types work at opposite ends of the COVID-19 spectrum — with the molecular tests of nasal or throat swabs finding the active presence of the virus, and the serological tests of blood serum finding virus-fighting antibodies after people have recovered. Walz has said both are needed to map the severity and course of the pandemic.

Mayo Clinic's commercial reference lab, the third largest in the country, already had capacity for 7,500 molecular diagnostic tests per day and has been a key resource early in the pandemic. About 25,000 such tests, more than half of the 41,675 performed so far in the state, were done by Mayo.

Now the Rochester, Minn., lab is looking to increase that capacity and double the number of antibody tests — from 10,000 to 20,000 per day — which among other things could be used for surveillance of entire work sites to determine which workers have recovered and are no longer infection risks.

The coronavirus that causes COVID-19 has proved more infectious than expected — with Chinese researchers publishing estimates in Nature Medicine this week that 44% of infections are transmitted before patients have symptoms.

Testing for immunity

Whether people have immunity following infection with this virus — which first emerged in December in Wuhan, China — is unclear, but research of the SARS coronavirus pandemic in 2002-2003 found evidence of immunity that lasted for years.

"We are inferring that there is protective immunity here," said Dan Huff, an assistant commissioner for the Minnesota Department of Health, in testimony regarding testing to the House Health and Human Services Finance committee on Thursday.

Republican lawmakers have grown increasingly critical of the economic toll of the ongoing statewide stay-at-home order.

At Thursday's Senate HHS Finance and Policy Committee hearing, Sen. Michelle Benson, R-Ham Lake, asked why the state was taking a broader stay-at-home approach when modeling showed similar outcomes under a scenario that restricted only the elderly and people with other health problems at greatest risk of complications from COVID-19.

Walz did not participate in a daily COVID-19 media briefing Thursday. But earlier this week, he said the state wasn't ready for a scaled-back approach until it had enough testing capacity to track the spread of the virus.

Mayo and the U aren't the only labs adding capacity. HCMC in Minneapolis can now conduct 600 diagnostic tests per day, which Dr. Daniel Hoody, chief medical officer, said is a key resource in an urban area given national studies showing that COVID-19 has been harder on minorities.

"The pattern is irrefutable," Hoody told lawmakers at the House hearing on testing.

With the addition of 103 lab-confirmed COVID-19 cases and seven deaths on Thursday, the Minnesota Department of Health reported a total of 1,912 cases and 94 deaths statewide. Limited testing has undercounted the true number of infections, though, with state health officials predicting there could be 100 cases for every lab-confirmed case.

State health leaders are preparing for the ramp-up in testing by discussing which priority groups should receive them first.

'Long ways to go'

The Health Department already has a long list of target groups for molecular testing, including people who get sick who are elderly, child-care workers or emergency first-responders, said Kris Ehresmann, state infectious disease director.

While testing of asymptomatic people could help identify more cases early on — when infected people appear at greatest risk of spreading the virus — Ehresmann said the state will continue to work through these high-risk groups first when they get sick.

"We will move to another level of symptomatic testing first before we would start asymptomatic testing," she said, adding that "we have a long ways to go."

The Health Department's priority list is only a guide, though, and one lab is planning to use its newly created capacity of 400 COVID-19 diagnostic tests per day in a different way.

OralDNA Labs in Eden Prairie plans to offer testing, symptoms or not, to all dentists in Minnesota, which could take the pressure off emergency departments that are receiving patients with dental emergencies. The lab also will offer testing for free to Eden Prairie firefighters.

"One of the characteristics of this virus that is so dangerous is that it can be spread by carriers who are completely unaware that they are infected," said George Hoedeman, chief executive of the lab. "Testing will be an important tool to reopen dental offices and the state of Minnesota."

Mayo and U officials also unveiled new forms of testing they are studying. Mayo researchers are trying to test for the presence of the coronavirus in tissues, which among other things would be important for evaluating transplant donors, and for ways to predict severe illness.

The U is exploring a faster diagnostic process, which might be slightly less accurate, Schacker said, but would cut out a prolonged step of extracting RNA from specimen samples, and would not require chemicals and supplies that are in short supply worldwide.

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Staff writer Glenn Howatt contributed to this report.