FDA Working With NCI, NIAID on SARS-CoV-2 Serology Test Validation Effort

This article has been updated with additional comment from the FDA.

NEW YORK – The US Food and Drug Administration on Saturday said that it will work with the National Cancer Institute and the National Institute of Allergy and Infectious Diseases to establish the validity of serological tests for determining whether individuals have antibodies to SARS-CoV-2.

In March, the agency issued guidance allowing serology tests to be launched on the market without Emergency Use Authorization, as long as the test providers notify the FDA that they've validated their tests. These tests cannot involve at-home sample collection, and test reports must alert patients that the tests have not been reviewed by the FDA and that negative results don't rule out SARS-CoV-2 infection, among other caveats. Around 13 labs and close to 100 manufacturers have chosen to launch serology tests via this pathway. 

Developers are also free to seek EUA for their serology tests, but the FDA has granted authorization to only four tests to date. More recently regulators have expressed concerns about the performance of serology tests not reviewed by the FDA and the claims that test providers are making about their products. As such, the agency has been intent on an "inter-agency" validation project for such tests to establish their performance. 

In its statement on Saturday, the agency confirmed that it is working with the NCI and the NIAID on this effort. The project will "establish a capability at [the] NIH to evaluate serological tests for developers," the agency said, adding that the effort will include tests already being marketed and those going through EUA.

The FDA is allowing labs and manufacturers to launch antibody tests for COVID-19 without EUA as long as such tests aren't marketed as standalone diagnostics for SARS-CoV-2 infection. However, the agency envisions that these tests can be useful for identifying individuals – including asymptomatic ones – who have had an infection and developed antibodies as their immune systems have successfully fought back against the virus.

The tests are being heralded as a tool that can be used to map the spread of COVID-19, and to identify individuals whose antibody-laden plasma may be used as a potential treatment for patients who are actively infected with the coronavirus. Local governments and employers are also considering deploying such testing broadly as stay-at-home orders are lifted as a way to identify people who can return to work.

However, validation studies have shown that these serology tests can have high false-positive rates, leading many to think they've developed immunity to COVID-19 and can safely reenter society, when they haven't. Additionally, the FDA alerted healthcare providers recently that providers of serology tests are falsely claiming they have garnered EUA or that their tests can diagnose COVID-19.

Earlier this month, NCI Deputy Director Douglas Lowy provided some details on a serology COVID-19 test validation project the institute is working on during a virtual advisory committee meeting. According to a presentation from that meeting, the NCI will use the expertise within its human papillomavirus (HPV) serology testing lab to validate COVID-19 serological tests. In addition to NIAID, the project will also involve experts within the Centers for Disease Control and Prevention, Mount Sinai in New York, and others. 

In the short term, the experts involved with the project will focus on establishing the performance of serological tests, including those submitted to the FDA for authorization, and correlate them with neutralization assays. They hope to understand if the tests are cross-reacting with sera from coronavirus exposure before this pandemic, making them more likely to yield false positives.

Longer term, the aim of the project is to better understand how long patients who test positive and have antibodies to COVID-19 remain resistant to infection. Experts also plan to monitor COVID-19 serology in cancer patients in a study.

"Performance assessments for serological tests will begin soon, and we expect to start seeing results shortly thereafter," the FDA said in its statement. "We will review NIH’s results expeditiously, and performance results from NIH’s assessment may complement and inform the determination of whether FDA issues an EUA for a particular test."

By the same token, information from the validation project could conceivably also be used to identify and remove problematic tests from the market from among the long list of tests that have launched without EUA. The FDA said after the publication of this article that the agency "can’t speculate on potential future actions regarding removal of tests from the market." 

In order for the validation project to have an impact, labs and manufacturers that have notified the FDA of launched serology tests but don't have EUA will have to voluntarily participate. Although test developers are asked to validate their serology tests before notifying the FDA and launching tests, submission of test validation data is not required as part of the notificaiton process. Several test developers have already voluntarily agreed to participate in the validation project with the NIH. 

Meanwhile, the FDA, in its statement, continued to encourage serology test providers to seek EUA. The agency said in its statement that it is working on an EUA template that will be available "in the coming days" and will hopefully streamline the authorization process for companies that choose to pursue that pathway.

"The bottom line is that FDA still expects tests to be validated even under our revised policy for tests," the agency said. "However, the EUA process or an evaluation by NIH supports greater confidence in test performance."

The agency said it is also working on making it more clear to the public which serology tests it has reviewed and which it has not. The FDA said it will continue to take enforcement action against test providers making false claims about their tests, and circulate educational materials with state governments, hospital systems, payors, and healthcare professional associations about the potential for false-positives with tests not reviewed by the agency.