FDA Streamlines Authorization of COVID-19 Molecular Test Pooling for Screening Programs

Last July, in an effort to meet the desperate need for high throughput COVID-19 testing, the U.S. Food and Drug Administration (FDA) issued the first clearance for use of a previously authorized test on pooled samples to Quest Diagnostics’ SARS-CoV-2 RNA test (See DTET, September 8, 2020). More than two dozen other COVID-19 tests have received Emergency Use Authorization (EUA) since then. Now the agency has doubled down by promulgating new rules making it easier for makers of previously authorized molecular tests to get expanded EUA for pooling.

COVID-19 Test Pooling

Pooling is a technique that enables laboratories to expand throughput by testing a batch of combined specimens at once. If the pool tests negative, it becomes unnecessary to test the constituent samples. The tradeoff is that the pooled samples must be diluted, which makes the nucleic acids produced by the SARS-CoV-2 virus more difficult to detect thus increasing the risk of false negatives. The other downside is that pooling can backfire and consume more testing time and resources when the sample comes back positive because the samples then need to be tested individually to detect the source(s) of the positive result.

For these reasons, the FDA has been historically reluctant to allow pooling. But with COVID-19 testing resources stretched so thin, the agency issued its first ever guidelines to help molecular test makers secure EUA for pooling. On April 20, the agency issued an amended version of those guidelines to facilitate authorization for pooling. The punchline: Molecular COVID-19 tests that have received EUA can be used with pooled samples performed to screen asymptomatic people as part of a “serial testing program,” such as in a school or workplace setting as long as the test developer self-certifies that it has validated the test for pooling.

“If a test developer has self-certified it has validated its test for pooling, FDA will add that test to a list of tests that can be used for pooling nasal specimens as part of a serial testing program,” noted the FDA’s device center director, Jeffrey Shuren, in a statement, describing the policy as a way to help schools, workplaces and others establish routine testing programs.

The New Pooling Protocols

The amendment applies only to pooling of anterior nasal respiratory specimens and tests being used at least once per week as part of a serial testing program. To qualify for use of a test on a pool of more than three specimens without first going through agency review, test makers must provide the FDA notification along with their validation data and the pooling procedures to be used, after which the test will be listed on the FDA website as allowed for pooling and updated labeling will be posted with the test’s EUA. They can place up to three samples in the same transport vial, the amended guidelines explain, including self-performed swabs and swabs collected by a healthcare professional, without additional validation, as long as the analysis is performed in certified CLIA laboratories.

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This article originally appeared in G2 Intelligence, Diagnostic Testing & Emerging Technologies, May 2021.