Compared viral RNA isolation protocols (magnetic beads-based method, column-based method) to ViRNAExTM extraction protocol in fresh and frozen virus transfer media of patients tested previously as COV2- positive. Obtained RNA has been used for GeneFirst™ qPCR testing of the genes: SARS-CoV-2- Gene N (A), SARS –COV2- ORF1ab (B), and epithelial cell control gene (C).
Analyzing the data from qPCR:
Figure 1: ViRNAExTM has comparable RNA-virus detection capacity if fresh virus transfer media is used for RNA isolation. The differences in Ct values were described on 24 samples and represent difference of
A. 1,7(Ct- cycle) for SARS –COV2-N gene)
B. 1,6 (Ct-cycle) for SARS-COV2-OFR1ab gene and
C. 3,3 (Ct- cycle) for epithelial control gene. Please see the Figure 1 A, B, C. The green amplification curve represents ViRNAExTM sample, the red one represents RNA separated by magnetic beads.
Figure 2: Similarly, on the Figure 2 the ViRNAExTM (Green , Red curve) is compared to the column-based RNA isolation (blue curve). In this case frozen virus transfer media of previously positive patients were used for comparisons (12 samples in total). We may see the significant delays in SARS-COV2- N gene (8 Ct cycles difference) and SARS- COV2 – ORF1ab gene (10 Ct cycles difference). The storage under freezing conditions did not influence the epithelial control gene detection. Green and red curves represent different starting concentrations of viral load.