Figure 5

Analysis of nasal swab and saliva samples collected from 29 inpatients hospitalized for COVID-19. (a) Table summarizes results of our research-based RT-PCR and ddPCR assays compared to CML nasal swab testing. Each number in the table represents cases detected as positive or negative by our assays and by the CML. For example, our saliva RT-PCR assay detected all (14 out of 14) positive patients that are detected as positive by the CML. On the other hand, our RT-PCR saliva assay detected an additional 9 positive patients that are deemed as negative by the CML. (b) The figure demonstrates N1 vs N2 target gene concordance assessed by RT-PCR Ct values (left), ddPCR positive droplet number (middle), and ddPCR copy number per µL (right). The dashed lines in each subplot indicate empirical thresholds for positive readout calling. (c) The comparison of matched saliva-based RT-PCR and ddPCR results with NS-based results generated by the diagnostic facility. For saliva ddPCR assay, a sample is called positive if either N1 or N2 are above the empirical thresholds. For saliva-based RT-PCR assay, a sample is called positive if either N1 or N2 show Ct values < 40. The green dots indicate positive sample status, while red dots indicate samples tested negative in respective settings. The maroon dashed lines indicate samples tested positive by the respective assays.