It took University of Minnesota researchers only a couple more weeks—after establishing the state’s fastest on-site COVID-19 testing facility—to refine and expand the laboratory-developed procedure (LDP) that tests for COVID-19, increasing testing volume to more than 300 tests per day. The team recently published their findings in “bioRxiv” in hopes of sharing what Andrew Nelson, MD, PhD, says is a “blueprint for others” that helps mitigate the impact of the nation’s testing supply shortage.

“Hundreds and hundreds of papers have been getting out there as the medical community and, frankly, the entire world are all simultaneously trying to understand the disease better, the testing and the treatment,” said Dr. Nelson, who is an assistant professor in the U of M Medical School’s Department of Laboratory Medicine and Pathology. “At a time with huge shortages in reagents and a lack of access to FDA-cleared kits, we wanted to put out our experience.”

The Role of Reagents

Reagents play a critical role to inactivate the virus during the extraction step of the testing process.

“It also concentrates the virus parts that you’re going to be testing to improve how easy it is for the test to detect the virus during the PCR (polymerase chain reaction) process,” said Sophia Yohe, MD, an associate professor in the Department of Laboratory Medicine and Pathology and medical director for M Health Fairview’s Molecular Diagnostics Lab. She led the team in mid-March to establish the COVID-19 testing facility in the University’s Biomedical Discovery District with the goal of finding new ways to test for COVID-19.

The specific reagents used in the U.S. Food and Drug Administration (FDA) approved kits are currently in low supply, but it’s well-known to researchers that other reagents may work similarly in their ability to detect COVID-19. With the implementation of the FDA’s special emergency rules for high-complexity laboratories with Clinical Laboratory Improvement Amendments (CLIA) certification, the U’s COVID-19 testing facility, which is CLIA-certified through the University of Minnesota Genomics Center (UMGC), set out to prove the effectiveness of different reagents.

“To be clear, it is not surprising to any research scientist that their standard research reagents would work in a clinical assay (testing procedure),” said Kenny Beckman, PhD, UMGC director. “The difficulty in validating a clinical test is that the burden of proof is much higher than many research scientists may realize; you have to prove that the assay works very, very reliably. The degree of failure that is not only acceptable—but absolutely common—in research lab work, is simply unacceptable in clinical assays. This paper shows people exactly what protocol to follow if they want to take research reagents and validate them for clinical use.”

In numerous instances, this team has validated their LDP, proving its equivalency to the FDA-approved kits and other instruments. Their first test sample validation, in partnership with the Minnesota Department of Health, helped launch the LDP. Subsequent cross-comparison work of test samples showed equivalent clinical performance with two other FDA-approved instruments as well. 

“This LDP has increased our test capacity for the institution, which is a good thing, but now we’ll also be able to do some comparisons between this LDP and the FDA-approved commercial kits, which we also hope will help the field understand how good the testing has really been,” Dr. Nelson said.

The Next Step in Testing

This LDP, which uses other available reagents and a smaller volume of those reagents during the PCR portion of the testing process, has more than doubled the daily capacity for tests. Between the U’s COVID-19 testing facility and the M Health Fairview’s Infectious Disease and Diagnostics Laboratory, the team can complete roughly 300 tests per day.

“Being able to spread that information and to help others think about things that they can do to also conserve reagents is important right now,” Dr. Yohe said.

That’s because conserving reagents and increasing testing volume will become especially important in the coming weeks across the nation, and Dr. Yohe says their LDP with flexibility, unlike the rigid, FDA-approved kits, creates new opportunities to meet the demand for future COVID-19 testing.

“We will be able to test alternative sample types that may be easier to collect than the nasopharyngeal swabs,” she said. “Also, some of the patients who have COVID-19 and have been on ECMO, which is basically temporary artificial heart and lungs, no one knows if those instruments can get contaminated with the virus. Our LDP has the flexibility to test those samples to see if there’s any evidence of contamination in that instrument.”

This past week, the team also began receiving more samples from local hospitals that were originally routed to the Mayo Clinic and has started supporting the testing needs for the U’s various clinical trials studying possible COVID-19 treatments as well as antibody testing.

Dr. Yohe says they will continue to improve the LDP to grow the testing volume even further in hopes of helping expand the types of people who can get tested for COVID-19—a key factor in battling the pandemic and preventing spread.

“We’re not testing people right now to see if they can go back to work, and I think there’s going to be demand to test for some of those roles in the future,” Dr. Yohe said. “Our goal is to get something that can be done at a much higher throughput and with supplies that are more widely available, so that we can look at testing the very large numbers you’re talking about when you start screening the whole state.”

Dr. Nelson added, “That’s hopefully, where we can continue to provide some support and just increase the overall capacity of what the University can do for patients over the coming months.”