FDA clarifies pooled sample, multi-analyte coronavirus EUAs

Developers of multi-analyte respiratory panels that include a test for SARS-CoV-2, the novel coronavirus, can request emergency use authorizations (EUAs) from the US Food and Drug Administration (FDA), the agency clarified this week.
 
In updates to its frequently asked questions (FAQ) webpage on SARS-CoV-2 testing, the agency said that multi-analyte respiratory panels that include SARS-COV-2 are eligible for emergency use authorization, noting “the overlap in signs and symptoms between SARS-CoV-2 and other respiratory viral infections, including influenza.” Citing increased speed and efficient use of resources, the FAQ adds that “These panels are useful when multiple respiratory pathogens are circulating at the same time, as is expected with the upcoming flu season.”
 
FDA will consider the intended use of the test, including fit within the emergency declaration of the Department of Health and Human Services and current public health recommendations for patient testing. The agency will also consider the in vitro diagnostic (IVD) status of the other components of the multi-analyte panel. Laboratories and commercial manufacturers should refer to their respective molecular diagnostic templates for validation recommendations and to determine what should be included in the EUA request.
 
In a new FAQ addressing point-of-care (POC) testing, FDA also refers manufacturers to the appropriate molecular diagnostic template for validation and EUA submission guidelines. An EUA for a test intended to be performed at POC should include “data to demonstrate that non-laboratory personnel can perform the test accurately in the intended use environment, as well as data to demonstrate the robustness of the device for near patient testing, i.e., that the device is not sensitive to environmental and usage variation,” according to the FAQ.
 
If the assay is to be used with a test system that has been reviewed and Clinical Laboratory Improvement Amendments- (CLIA-) waived, just the performance of the SARS-CoV-2 assay itself must be tested. The previous CLIA waiver categorization, says FDA, can generally be leveraged to obviate the need for additional test data to support that the test is simple enough for POC use, so long as nothing about the coronavirus assay itself would complicate testing.
 
The expectation for diagnostic POC tests is that they demonstrate both positive and negative agreement of at least 95%, though positive agreement of at least 80% “may be appropriate with appropriate limitations added to the intended use that would mitigate the risk of false negative results,” says the FAQ.
 
FDA
 
The agency also updated a FAQ regarding pooling individual SARS-CoV-2 diagnostic tests. FDA identified two strategies: samples can either be pooled by combining aliquots of transport media, each of which contain a single patient sample, or multiple patient swabs can be put into a single volume of transport media. Validation recommendations for each pooling approach are contained in the appropriate molecular diagnostic templates.
 
However, “FDA recommends validating your test with either pooling approach in a way that preserves the sensitivity of your test as much as possible; that is, it is preferable to use an approach where all specimens identified as positive when tested individually are also identified as positive when tested using the pooled testing approach,” clarified the agency.
 
The small reduction in sensitivity from pooling, says FDA, is offset by the large increase in testing capacity that can be effected by sample pooling. Accordingly, FDA recommends that test performance reaches at least 85% positive agreement compared with the performance of the same test performed on individual samples. Manufacturers should include a monitoring plan in the tests’ use instructions.