CARSON CITY, Nev. (AP) — As facilities throughout the United States prepare to expand the use of rapid coronavirus tests, Nevada officials are weighing how to incorporate them into the data they present to the public.
Since the start of the pandemic, the state has relied heavily on molecular tests – nasal or throat swabs that detect the virus’ genetic material. The tests are comparatively expensive and time-intensive, requiring health care workers to collect and test samples.
Officials have expressed skepticism over tests found to be less accurate, including antigen tests, which check for viral proteins rather than the virus itself, and antibody tests, which check blood for proteins the body creates to fight the virus.
But now they are re-examining these tests and how to best use them.
After entering into a $760 million contract with medical device company Abbott Laboratories, the federal government is preparing to deploy 150 million rapid antigen tests to strategic sites throughout the country, including to Nevada. These tests yield results in minutes, but they are generally considered to be a less accurate measure of infection.
Nevada officials expect the federal government to expand the use of antigen testing at places like nursing homes or schools. Cartridges needed to process them have already been provided to skilled nursing facilities in Las Vegas.
“There’s a change going on within the stream of tests that are going to public health labs,” Nevada COVID-19 task force director Caleb Cage said in early September.
As antigen tests become increasingly in use, states will also have to determine how to most accurately report results. The question mirrors earlier challenges that plagued states in the spring over how to distinguish between molecular and antibody tests.
In more than 20 states, officials do not release complete data on antigen tests or distinguish between different kinds of tests in the data they report to the public, according to a Kaiser Health News report. In Nevada, labs are already directed to report both antigen and molecular tests to the state. The state dashboard shows Nevada has processed nearly 1 million molecular tests. Efforts to report antigen and molecular tests separately are underway, the Department of Health and Human Services said.
“At this time, we are unable to provide specific statistics on point-of-care testing alone as the current system is not able to comprehensively identify those separate from laboratory based molecular testing,” department spokeswoman Shannon Litz said.
On Aug. 28, Nevada issued a technical bulletin for testing facilities that wish to use rapid tests. The bulletin directed facilities to confirm positive rapid tests with molecular tests and advise symptomatic individuals whose tests come back negative to be swabbed for a molecular test.
Distinguishing between the two tests could affect decisions about the future of the state’s pandemic directives, including business closures, capacity caps on public places and the face-covering mandate.
Nevada Public Health Laboratory Director Dr. Mark Pandori has long been skeptical of using antigen tests to diagnose COVID-19, but he acknowledged the push to apply them at a wider scale. Nevada has to present a clear message to the public about its testing methods, he said.
Pandori said the state’s technical bulletin reflected how antigen tests that yield positive results are generally reliable, while negative results can be less so because the tests frequently do not detect cases with low viral loads. It makes sense, he said, to refer symptomatic individuals for molecular testing regardless of whether their tests come back positive.
“The only flaw, really, in these antigen tests is sensitivity. They will miss cases, but how relevant the cases that are missed are, we still don’t know. They could be missing very low positives that aren’t a public health threat,” Pandori said, explaining the tests’ shortcomings in detecting low viral loads.
Like the U.S. Centers for Disease Control and Prevention, Pandori sees molecular tests as the gold standard, but he believes any data gathering is worthwhile.
“What rapid testing allows you to do is cast a much wider net in terms of the gathering of public health intelligence, and also the ascertainment of infected individuals. So it’s better than nothing,” he said.
Sam Metz is a corps member for the Associated Press/Report for America Statehouse News Initiative. Report for America is a nonprofit national service program that places journalists in local newsrooms to report on undercovered issues.