Group Testing for Sars-Cov-2 to Enable Rapid Scale-Up of Testing and Real-Time Surveillance of Incidence

Pilcher, Christopher D; Westreich, Daniel; Hudgens, Michael G

High-throughput molecular testing for SARS-CoV-2 may be enabled by group testing in which pools of specimens are screened, and individual specimens tested only after a pool tests positive. Several labs have recently published examples of pooling strategies applied to SARS-CoV-2 specimens, but overall guidance on efficient pooling strategies is lacking. Therefore we developed a model of the efficiency and accuracy of specimen pooling algorithms based on available data on SAR-CoV-2 viral dynamics. For a fixed number of tests, we estimate that programs using group testing could screen 2 to 20 times as many specimens compared to individual testing; increase the total number of true positive infections identified; and improve the positive predictive value of results. We compare outcomes that may be expected in different testing situations and provide general recommendations for group testing implementation. A free, publicly-available web calculator is provided to help inform laboratory decisions on SARS-CoV-2 pooling algorithms.