Covid-19 Serology Tests Important Focus: CDRH

The development of serology tests for Covid-19 detection is of “growing importance” in CDRH’s response to the ongoing coronavirus health emergency, Center Office of In Vitro Diagnostics and Radiological Health director Timothy Stenzel said during a 4/8 virtual town hall teleconference on diagnostic tests. The tests will likely play a huge role in identifying individuals who have overcome an infection in the past and have developed an immune response. The agency believes serology tests could also be used to help identify, together with other clinical data, individuals who are no longer susceptible to infection and can return to work. Additionally, the tests can aid in determining who may donate a part of their blood called convalescent plasma, which may serve as a possible treatment for those who are seriously ill from Covid-19.  

Because of the initial slow rollout and criticism involving Covid-19 testing, FDA said it wanted more flexibility for serological tests in an effort to provide laboratories and health care providers with early access to the tests with the understanding that the FDA had not reviewed or authorized (or “approved”) them, at least not initially, and the tests should not be used for diagnosing or excluding active infections. Specifically, last month, FDA issued a policy explaining that it does not intend to object when developers of serological tests market or use their tests without prior FDA review where: (1) the tests are validated by the developer to determine that they are accurate and reliable, (2) notification of the developer’s validation is provided to FDA, and (3) the tests are labeled appropriately, including that they are not to be used as a sole basis for diagnosis.

Lately, Stenzel said serology test accuracy is getting increasing attention at CDRH. The tests can come to market using pathway C or pathway D under the agency’s 3/16 guidance entitled “Policy for Diagnostic Tests for Coronavirus Disease-2019 during the Public Health Emergency.” Many developers have used pathway D, Stenzel said, which is “where they notify FDA that they have completed validation and then once there are a few exchanges to understand that everything is being addressed as described in the guidance, then those developers receive a confirmation message and are allowed on the market.” Because of accuracy concerns, Stenzel said that FDA is collaborating with other agencies to create an interagency program to help address and verify test accuracy. Developers can participate in the program and send their point-of-care test kits, including any instrumentation that might be needed, to a central location where the performance of the tests will undergo an independent assessment. For more information on the program, interested test developers should send an email to CDRH-EUA-Templates@fda.hhs.gov.

During the teleconference, Stenzel also addressed general questions received recently. One question from developers asked what should be done regarding validating alternate supplies, such as alternate viral transport media, swabs, extraction reagents and instruments. He said that if the developer has an Emergency Use Authorization (EUA), or has submitted an EUA, then they can simply do a bridging study with the alternate reagents or supplies and validate those to current CLIA standards and begin using them. “You do not need to submit an amendment or submit an application to FDA,” he said. “If you are a lab using someone else’s EUA-authorized device, you can do the same thing without submitting anything to FDA. However, in both situations we would love to see the validation data generated because it might be helpful to others. It is not required to be submitted, but would love to see it.”

For test manufacturers who have an alteration to their product, validation and submission to FDA is required in the form of a supplement, Stenzel said. For those interested in developing home tests, he recommended developers “reach out” in an email (covid19dx@fda.hhs.gov), and then the Center will work with the firm to design the appropriate study to assure that home collection is safe and accurate. “We are working with a number of developers now and hope to have some news on these EUAs shortly,” he said.