Conclusions
Grouping samples into pools of five for RT-qPCR resulted in an increase in SARS-CoV-2 testing capacity with minimal loss of sensitivity compared with testing each sample individually.
Methods
Various pool sizes (five, 10 and 15 samples) were evaluated prior to RNA extraction followed by standard RT-qPCR for the diagnosis of COVID-19. The pool size achieving reproducible
Results
A pool size of five samples had higher sensitivity compared with pool sizes of 10 and 15 samples, showing a mean cycle threshold (Ct) shift of 3.5 [standard deviation (SD) 2.2] between the pooled test and positive samples in the pool. Next, a pool size of five was used to test a total of 895 pools (4475 prospective samples) using two different RT-qPCR kits. The Real Accurate Quadruplex corona-plus PCR Kit (PathoFinder) reported the lowest mean Ct shift [2.2 (SD 2.4)] between the pool and individual samples. This strategy enables detection of individual positive samples in positive pools with Ct of 16.7-39.4. Conclusions: Grouping samples into pools of five for RT-qPCR resulted in an increase in SARS-CoV-2 testing capacity with minimal loss of sensitivity compared with testing each sample individually.