Retrospective analysis of SARS-CoV-2 RNA detection in pooled saliva samples: An effective cost saving method.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a causative agent of coronavirus disease 2019 (COVID-19), first reported in December 2019. The virus rapidly spread throughout the globe. Laboratory investigations play an essential role in the early and effective detection of SARS-CoV-2-infected individuals to prevent transmission. Objectives: The saliva pooling system to screen SARS-CoV-2 in the population has been applied to increase the surveillance widely and conveniently among healthcare personnel at King Chulalongkorn Memorial Hospital. The Ct-values of positive pools and positive individual samples were compared, and the cost effectiveness was also evaluated. Methods: The retrospective study was conducted with 24,098 samples between April 19, 2021, and May 30, 2022, to be tested for the presence of SARS-CoV-2. The samples were examined individually and in pools of four and six by using the Cobas 6800 SARS-CoV-2. Results: The prevalence of SARS-CoV-2 infection was 0.51% (123/24,098). The present study showed that saliva pools of four or six samples do not compromise viral RNA detection. Pooled testing of saliva samples revealed high performance for detection of SARS-CoV-2. Pooling of four and six resulted in a cost reduction of 73.47% and 80.69%, respectively when compared to individual testing. Conclusion: Screening saliva pooling for SARS-CoV-2 is useful in identifying infections in healthcare workers. Saliva testing allows for rapid personnel isolation and prevents further transmission; therefore, it could be considered an alternative method in low-prevalence settings.