Pool testing is a strategy in which samples from several people are tested together for SARS-CoV-2. This allows more samples to be tested quickly while utilizing fewer resources. If a pooled test result is positive, each of the samples are then individually tested to determine which samples are positive. This strategy is recommended for use in low prevalence settings, where most results are expected to be negative. In places where routine, repeat testing is needed such as businesses, dorms, and schools, this method can also be especially useful as a cost-effective screening tool for asymptomatic individuals (Lakdawalla et al).
Because pool testing efficiency varies with prevalence, test sensitivity, and patient pool size, one potential limitation is that positive samples in larger groups may be diluted, leading to a higher false-negative rate (Cherif et al. 2020). Studies have shown pooling to be most effective when the incidence rate of SARS-CoV-2 infection is 10% or less (Abdalhamid et al. 2020) and with pool sizes of 4-30 samples (Lohse et al. 2020).
The first EUA for pool testing was approved on 7/18 to the Quest SARS-CoV-2 rRT-PCR test.
In silico testing analysis by Quest found that, none of 3,091 total specimens from a population with a prevalence rate of 1-10 percent, if pooled, would have been incorrectly determined to be negative. This is encouraging data for clinical use of this test for screening of asymptomatic individuals in low-prevalence settings. As of 8/1/2020, the FDA has approved 3 tests for pooled testing, all of which use RT-PCR and oro/nasopharyngeal swabs.
References
Abdalhamid, Baha et al. 2020. “Assessment of Specimen Pooling to Conserve SARS CoV-2 Testing Resources.” American Journal of Clinical Pathology 153(6): 715–18.
Cherif, Alhaji, Nadja Grobe, Xiaoling Wang, and Peter Kotanko. 2020. “Simulation of Pool Testing to Identify Patients With Coronavirus Disease 2019 Under Conditions of Limited Test Availability.” JAMA Network Open 3(6): e2013075–e2013075.
Interim Guidance for Use of Pooling Procedures in SARS-CoV-2 Diagnostic, Screening, and Surveillance Testing. (2020, August 1). Retrieved August 02, 2020, from https://www.cdc.gov/coronavirus/2019-ncov/lab/pooling-procedures.html
Lakdawalla, Darius, Emmett Keeler, Dana Goldman, and Erin Trish. “GETTING AMERICANS BACK TO WORK (AND SCHOOL) WITH POOLED TESTING.” : 14.
Lohse, Stefan et al. 2020. “Pooling of Samples for Testing for SARS-CoV-2 in Asymptomatic People.” The Lancet Infectious Diseases 0(0). https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30362-5/abstract (August 1, 2020).
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