Validation of SARS CoV-2 detection by real-time PCR in matched pooled and deconvoluted clinical samples before and after nucleic acid extraction: a study in tertiary care hospital of North India

Abstract

The diagnosis of coronavirus disease-19 (COVID-19) relies on the detection of severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) RNA by real-time reverse-transcription polymerase chain reaction in respiratory samples. Rapid increase in the COVID-19 cases across the world requires fast and efficient testing as testing capacity is a bottleneck in diagnosis. In this context, pooling strategy can be opted for rapid testing in a cost-effective manner. In this study, the authors have optimized and compared the effect of pooling (5 and 10 samples) before and after nucleic acid extraction. It was concluded that there was no significant difference in the SARS CoV-2 RNA detection in the pools prepared at sample or RNA level. Even after pooling, 10-fold dilution was detectable with 3-cycle threshold value change in both type of pools when compared with individual samples. Hence, sample pool size of 10 can be used in low-prevalent areas, and testing capacity can be substantially increased.

Keywords: COVID-19; Cycle threshold; Deconvolution; Nucleic acid testing; Pool testing.