NEW YORK – In a weekly call with developers of SARS-CoV-2 diagnostic tests, the US Food and Drug Administration strongly encouraged the off-label use of Emergency Use Authorized tests to detect for the virus in asymptomatic people. The agency also encouraged developers of fully at-home tests to consider ways that results can be reported to local public health departments.
On Wednesday Timothy Stenzel, director of the Office of In Vitro Diagnostics and Radiological Health at FDA's Center for Devices and Radiological Health, asserted that the agency is allowing antigen and molecular diagnostic tests to be used off-label in testing asymptomatic patients, as directed by a prescriber for prescription-use tests.
"That is completely legitimate to do, we are encouraging it, because we only have a small number of tests that are authorized for asymptomatic screening," Stenzel said on the call.
In particular, Stenzel said all of the EUA direct antigen tests can be used for this purpose.
Overall, "There are rare examples where we've seen asymptomatic data that is not sufficient for authorization and we make a very rare and unusual statement in the Instructions for Use," he said.
Stenzel noted however that the performance in this off-label setting is still unknown. "That should be understood by the prescribers," he said, and test results should be considered in the context of local incidence to help determine whether a confirmatory test is warranted.
That said, "We are encouraging more and more submissions for asymptomatic screening claims, and we welcome those, but in the interim we've made this very clear, and [the Centers for Medicaid and Medicare Services] and HHS have made this very clear as well, and removed any potential roadblocks at the federal level," Stenzel said.
Last month, FDA had updated its FAQ page to note that EUA tests can be used at the discretion of a healthcare provider.
The FAQ notes that SARS-CoV-2 molecular diagnostic tests have been authorized for use in individuals suspected of COVID-19 by their healthcare providers, and individuals suspected of COVID-19 infection or exposure can be symptomatic, pre-symptomatic, or asymptomatic. "Testing of any of these individuals is at the discretion of the healthcare provider ordering the test," it says. "Additionally, certain SARS-CoV-2 molecular diagnostic tests have been authorized with a screening claim for use in individuals without symptoms or other reasons to suspect COVID-19," the FAQ also says.
On Wednesday's call with developers, Stenzel also commented on the authorization of an over-the-counter fully at-home test from Ellume, and announced the at-home indication for the Abbott BinaxNow test.
The agency is "extremely excited" about these authorizations, and "We look forward to more and more home testing authorizations, not just for antigen and molecular tests, but also for serology tests," Stenzel said.
He also mentioned a recent prescription-use, at-home molecular test, referring to the Lucira COVID-19 All-in-One Test Kit from Lucira Health which received EUA last month.
"Of course, molecular is great if it can be done in the home environment. There is a challenge though in that it is more difficult to manufacture molecular tests in quite the same volume as direct antigen lateral flow tests," Stenzel said, adding that there may also be "cost differentials" between antigen and molecular testing.
Stenzel added that the manufacturing capacity for paper-strip antigen tests is in the tens of millions per month, if not in the hundreds of millions, from each manufacturer.
"There is a desire out there to have a lot more testing, there is a willingness to do this, so we're looking at how we can make that testing as widely available as possible, so that consumers and home users can get a fast, accurate result that they can use to make the very best decisions about their lives and those of their loved ones," Stenzel said.
In response to a question from a developer, Stenzel commented that reporting of test results to the appropriate public health agencies is "strongly encouraged," even for home tests without a corresponding app.
The Ellume test is paired with an app that enables reporting to a public health authority, while Abbott is partnering with eMed to allow reporting of test results in the BinaxNow home-use indication using its NAVICA app.
"It is obviously critical that the US government and public health authorities have data on where virus is going up and where virus is going down," Stenzel said. "The more we have that information in real time, the faster we can make assessments," he added.
"While it is not what I would call a decision requirement for an EUA, we encourage developers to think about this," he said.
Indeed, the first at-home test authorized, Lucira Health's test, did not have a reporting mechanism component, Stenzel said. "We asked them as part of the post-market commitment to come up with a plan to be able to provide home users ... or their prescribers to be able to report that information."
Stenzel also noted that a US government design competition, or "app-a-thon," recently concluded that aims to identify reporting technologies that could be used independent of specific tests.
"If a given small developer of a test doesn't really have the capability to think about this, then having an off-the-shelf app that could be used for them would be awesome," Stenzel said. "We are pushing that forward."