From the JHU Center for Health Security COVID-19 Updates:
POOLED TESTING As the United States and other countries look ahead to more fully relaxing social distancing measures, testing capacity is a critical barrier to proceeding with these plans. Pool testing, a method of testing patients for SARS-CoV-2 as a group instead of as individuals, is one potential option to dramatically increase testing capacity. Pool testing combines samples from multiple individuals in order to reduce the amount of testing materials needed to conduct tests (compared to multiple individual tests) and return results to individuals more quickly. If the pooled sample tests negative, then it can be assumed that nobody in that pool is infected, and no further testing is necessary. If a sample is positive, then each person in that pool can be tested individually to determine who among them is infected. In low prevalence settings, pooling the samples can reduce the overall tests performed.
Dr. Deborah Birx, the White House Coronavirus Response Coordinator, stated that the method could increase testing capacity by 900%, which would enable the United States to conduct 5 million tests per day. The US FDA is working to validate pooled sample techniques. A study published in The Journal of the American Medical Association: Network Open illustrates the potential benefits of pooled testing, particularly if disease prevalence in the test population is less than 30%. The authors warn that false negatives could increase due to pooled sampling techniques due to diluting positive samples with multiple negative samples, so test characteristics and processes could be closely selected and monitored.