Fast and widespread testing is seen as one of the keys to keeping the coronavirus under control. Experts say it would allow schools and businesses to reopen with the peace of mind that those infected with the disease were being identified quickly and staying home.
But testing in Utah and across the country has long been plagued by delays, as hospitals and labs face high demand and limited supplies to go around. Now, health experts nationwide are arguing faster, cheaper antigen tests should be deployed on a grand scale, to test mass amounts of people frequently and repeatedly.
There are two main kinds of tests for detecting when COVID-19 is actively affecting someone — molecular tests, which look for the virus’s genetic material, and antigen tests that detect proteins on the surface of the virus. Antibody tests are in another category, used to see if someone already had the virus.
Most hospitals and labs in Utah — and across the country — rely on molecular testing, said Dr. Bert Lopansari, with Intermountain Healthcare. That’s largely because PCR tests, as they’re commonly referred, are reliable. They are up to 98% accurate in detecting if someone has the virus.
“Even if the tiniest amounts are there, the molecular tests will amplify it and it will create millions of millions of copies so that it can be detected,” Lopansari said.
But the process is complicated, and requires time to go from the provider to the lab and processing up front.
In Utah, it typically takes about one to three days on average for test results to come back, according to Department of Health Deputy Director Nate Checketts. But a recent state audit found times also varied widely across labs, with many taking five days or more to return. One took up to three weeks. The average also didn’t account for what the auditors called “the most critical measure, which is the full turnaround time from swab to patient notification.””
By contrast, antigen tests can provide results in about 15 minutes. They’re also cheaper than the standard test.
Antigen testing machines for other illnesses — such as the flu or strep throat — are widely available in hospitals and clinics around the state, said Checketts. But the modifications that allow them to detect COVID-19 are not. At around $20-30 per test, they’re cheaper than the molecular tests, he said, but not so cheap that they could be used as widely as argued.
And even if the tests were already capable of being deployed on a wider scale, some Utah experts aren’t convinced they’re the solution.
Antigen tests are far less accurate than the molecular versions, said Lopansari. They look for virus proteins, but do not amplify them like molecular tests do. And because proteins can break down, the antigen tests have a shorter window of when they can detect the virus.
“I liken them to digital cameras,” Lopansari said. “So the molecular tests are like your 24 megapixel camera. You can detect fine details in the background. Whereas the antigen tests are more like your six to 10 megapixel camera — you can detect the obvious, but you might not be able to detect the fine details.”
And while proponents argue that frequent testing would eventually catch cases that might have been missed at first, Dr. Jonathan Genzen, chief operating officer at ARUP Laboratories, isn’t convinced that’s a realistic solution.
“I don’t dispute the concept,” Genzen said. “But it reflects an idea of unlimited testing resources, and that has been a challenge certainly that we've seen in the clinical laboratory space,”
Still, Checketts said the state is “heavily engaged” in increasing antigen testing.
He said Utah received 15 machines earlier in the year, which were sent to tribal facilities and correctional facilities. The state is also working with local health departments to develop a list of over 100 sites where more machines should go when available, such as homeless resource centers.
He said the federal government is also rolling out a massive program across the country to get antigen tests to nursing facilities, some of which have already come to Utah.
For all the promise of widespread testing, Genzen said it’s still only part of the solution. It won’t take away the need for individuals to behave responsibly.
“Mask use, physical distancing, hand hygiene, being attentive to symptoms, goes a very, very long way,” he said. “Those are the critical pieces for how we keep our workforce healthy and how we continue to support testing as well.”
Jon Reed is a reporter for KUER. Follow him on Twitter @reedathonjon
