Clarity Plus™ digital PCR: A novel platform for absolute quantification of SARS-CoV-2

In recent years, the usage of digital polymerase chain reaction (dPCR) for various clinical applications has increased exponentially. Considering the growing demand for improved dPCR technology, the Clarity Plus™ dPCR system which features enhanced multiplexing capability and a wider dynamic range for nucleic acid analysis was recently launched. In this study, a dPCR assay optimized for use on Clarity Plus™ was evaluated for the absolute quantification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent responsible for the global coronavirus disease 2019 (COVID-19) outbreak. The assay demonstrated good inter- and intra-assay precision, accuracy, as well as excellent linearity across a range of over 6 orders of magnitude for target gene quantification. In addition, comparison of the assay on both dPCR and qPCR platforms revealed that dPCR exhibited a slightly higher sensitivity compared to its qPCR counterpart when quantifying SARS-CoV-2 at a lower concentration. Overall, the results showed that the dPCR assay is a reliable and effective approach for the absolute quantification of SARS-CoV-2 and can potentially be adopted as a molecular tool for detecting low viral load in patients and wastewater surveillance of COVID-19.