On June 16, the US Food and Drug Administration (FDA) issued new guidance addressing two key issues related to SARS-CoV-2 testing: validation processes for test pooling of samples for test development and Emergency Use Authorization (EUA) purposes and screening of asymptomatic persons. The Diagnostic Challenge: Pooling of Samples Pooling is a technique that involves mixing aliquots, i.e., sub-samples extracted from individual samples into a pool or “batch” that can be tested with a single test. If the entire pool returns a positive result, the individual samples are retested to locate the source of the positive; but if the batch tests negative, all of the constituent samples are also deemed to be negative. Historically, developers of EUA tests have used pooling to modify how those tests are used. In the context of the current pandemic, pooling offers the advantage of conserving testing resources that have been in short supply. The downside of pooling is that it dilutes the nucleic acids produced by the SARS-CoV-2 virus, creating the risk of false negatives. As a result, test producers who use pooling must account for the false negative effect in validating the modified use. The FDA Guidance on Pooling The new FDA guidance, which […]