User:Shawndouglas/sandbox/sublevel1

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Another method some labs are taking to speed up turnaround time is using pooled testing. The general concept involves placing two or more test specimens together and testing the pool as one specimen. The most obvious advantage to this is that the process saves on reagents and other supplies, particularly when supply chains are disrupted, and it reduces the amount of time required to analyze large quantities of specimens.[1] This methodology is best used "in situations where disease prevalence is low, since each negative pool test eliminates the need to individually test those specimens and maximizes the number of individuals who can be tested over a given amount of time."[2] However, it's best left to situations where expectations are that less than 10 percent of the population being tested is affected by what's being tested for.[2][3][4]

The downside of pooled testing comes with the issues of dilution, contamination, and populations with 10 or more percent infected. A target-positive specimen that commingles with other target-free specimens is itself diluted and in some cases may cause issues with the limit of detection for the assay. Additionally, if the pool tests positive, target-free specimens may become contaminated by a target-positive specimen. This may cause issues with any individual specimen assays that get ran. And the workflows involving pooling must be precise, as a technician working with multiple specimens at the same time increases the chance of lab errors.[2][3][4] Finally, at least in the U.S., a Food and Drug Administration (FDA) emergency use authorization (EUA) for a validated pooled testing method is required.[2] (Validation of pooled methods may differ in other countries.[3]) The U.S. Centers for Disease Control and Prevention (CDC) has published interim guidance on pooled testing strategies for SARS-CoV-2.

On April 20, 2021, the FDA updated its policies to allow for pooled testing to be added to the use case scenarios for several existing test kits. "This means that tests with EUAs that are amended by this authorization may be used with pooled anterior nasal specimens from individuals without known or suspected COVID-19 when such individuals are tested as part of a testing program that includes testing at regular intervals, at least once per week."[5] However, affected kits can only be used in high-complexity CLIA labs, though "tests authorized for use in specific named or designated high-complexity laboratories can only be used in such laboratories."[5] As of September 2021, four PCR test kit EUAs were amended to allow for pooled testing[5]:

  • Biomeme SARS-CoV-2 Real-Time RT-PCR Test
  • Clinical Enterprise SARS-SoV-2-RT-PCR Assay
  • CRSP SARS-CoV-2 Real-time Reverse Transcriptase (RT)-PCR Diagnostic Assay (Version 3)
  • Viracor SARS-CoV-2 assay

References