Responding to limitations in existing testing methods, health care companies around the world are racing to produce new point-of-care diagnostic systems that can quickly detect the presence of the new coronavirus.

All of the existing devices used to diagnose COVID-19 cases, including Roche's system heralded by President Donald Trump on Friday and a second one from Thermo Fisher Scientific, are laboratory-based systems that require sophisticated analyzers in major hospitals and labs.

Like other systems to detect the virus, the Roche and Thermo Fisher systems are known as RT-PCR systems, for reverse-transcription polymerase chain reaction. That means the systems diagnose a viral presence when it reacts to specific snippets of genetic material.

Such systems can be highly accurate, but they often require hours to generate a result and another 24 to 48 hours if the patient's sample needs to be transported to a central lab for processing. Patients may continue spreading the virus during those time lags.

There's also a biological delay. The COVID-19 virus takes more time than past viruses to build up enough genetic material to be detectable with a lab-based test. That means a person may be contagious before the virus is detectable with traditional systems.

"Usually, you'd be able to detect it pretty close to when symptoms appear, for most viruses," said David Deetz, CEO of St. Paul's Ativa Medical, which is developing a point-of-care test that is still months from commercial release. "That's why no one can contain this thing. … You become contagious early and can't detect it until late. That's the main problem."

More than a dozen companies, including Ativa, are working on point-of-care systems that could offer rapid early detection of the virus, said Divyaa Ravishankar, a global product marketing manager with Ohio-based medical research organization NAMSA.

Other companies working on point-of-care systems include California's Nanomix, Washington-state based InBios International and New York-based Chembio Diagnostic Systems, Ravishankar said. North Carolina's BioMedomics is working to get FDA approval for a Chinese-made test that reportedly can deliver a result in 15 minutes.

Ravishankar said money has been "unlocked" at major funding agencies to help smaller firms accelerate development of COVID-19 diagnostic tests, including the federal Biomedical Advanced Research and Development Authority, the National Institutes of Health and the Gates Foundation.

No point-of-care system to detect COVID-19 is approved in the U.S. today. But like other point-of-care tools to detect illnesses, a quick test for COVID-19 would likely offer a trade-off between accuracy and speed, Ravishankar said.

Such a system could offer a result while the patient is still in the clinic, or standing in the entryway at a nursing home. Eventually it could be available over the counter at pharmacies, like an HIV test.

The result would not be definitive — people who test positive with a point-of-care test would likely need a full lab test to confirm the result, similar to a pregnancy test. But patients would at least know they need to take action until the definitive results are available.

"Most of the point-of-care systems are typically like a screening tool," Ravishankar said.

Kris Ehresmann, director of the infection disease division at the Minnesota Department of Health, said Sunday that the public has gotten conflicting messages regarding testing for COVID-19.

"The goal for everyone to have access to testing is aspirational," Ehresmann said Sunday. "The global demand for many of the components that are necessary to test for it is obviously extremely high. … We'd like to have more testing, but it is really not possible."

In the United States, the first COVID-19 test available was a RT-PCR kit sent out by the Centers for Disease Control and Prevention. The diagnostic kit included a critical component that has since come into short supply, which is an RNA extraction tool made by a company called Qiagen. (Thermo Fisher announced March 3 that it intends to acquire Qiagen in a deal valued at $11.5 billion.)

Dr. Ashley Haase, head of the Microbiology and Immunology Department at the University of Minnesota, said once the RNA is extracted from a patient's sample, it is transformed and amplified so it can be tested for specific snippets of genetic code using a PCR system.

"We've all been using these kits for RNA extraction for any number of kinds of research," Haase said. "It's easy to imagine that as the number of kits expands exponentially, that you may get shortages of some of the components."

On Friday, President Donald Trump announced that the Food and Drug Administration issued an "emergency use authorization" to the Switzerland-based Roche Group to begin selling its real-time RT-PCR test, in which patient samples are fed into Roche's fully automated cobas 6800 and cobas 8800 systems. Roche says the system can provide 96 test results in about three hours.

Soon after, Massachusetts' Thermo Fisher Scientific announced its own FDA emergency authorization to run a COVID-19 diagnostic test on its Applied Biosystems 7500 Fast Dx real-time PCR system. The test is designed to produce results within four hours of the lab receiving the patient sample.

But interest in development of a rapid point-of-care test will continue to build as the U.S. outbreak rolls on through 2020.

Dr. Mark Schleiss, a pediatrician at the University of Minnesota with a focus on infectious diseases, responded "Heck yes!" when asked whether the medical community would embrace point-of-care testing for COVID-19.

"What a boon it would be to have this for COVID-19," he said via e-mail. "It would be enormously valuable."

Joe Carlson • 612-673-4779