Fig. 2.

Comparison of RT-SARS, AlinSARS and Inhouse cycle thresholds in positive SARS-CoV-2 specimens.

Fifty samples positive for SARS-CoV-2 by Inhouse were retested with RT-SARS and AlinSARS showing concordantly positive results with the Inhouse E gene target (100 % PPA). Eight samples were negative in the RdRp gene target of Inhouse (84 % PPA). However, samples with one or two positive targets by Inhouse had been considered positive after confirmation by Allplex. The observed mean Ct differences between the assays were 1.2 Ct (mean of Inhouse target regions minus AlinSARS), 13.9 Ct (mean of Inhouse target regions minus RT-SARS), and 12.7 Ct (AlinSARS minus RT-SARS), the latter two mean Ct differences reflecting the 10 unread cycles of RT-SARS. The positive samples in the figure are presented in ascending order of Ct values by RT-SARS. In addition, 50 SARS-CoV-2 negative specimens by Inhouse retested with RT-SARS and AlinSARS were found negative, respectively (100 % NPA).