Assessment of Ion S5 NGS protocol for SARS-CoV-2 genome sequencing

Monitoring of the lineages SARS-CoV-2 is equally important in a fight against COVID-19 epidemics, as is regular RT - PCR testing. Ion AmpliSeq Library kit plus is a robust and validated protocol for library preparation, but certain optimizations for better sequencing results were required. Clinical SARS-CoV-2 samples were transported in three different viral transport mediums (VTM), on arrival at the testing lab, samples were stored on -20OC. Viral RNA isolation was done on an automatic extractor using a magnetic beads-based protocol. Screening for positive SARS-CoV-2 samples was performed on RT–PCR with IVD certified detection kit. This study aims to present results as follows: impact of first PCR cycle variation on library quantity, comparison of VTMs with a quantified library, maximum storage time of virus and correlation between used cDNA synthesis kit with generated target base coverage. Our results confirmed the adequacy of the three tested VTMs for SARS-CoV-2 whole-genome sequencing. Tested cDNA synthesis kits are valid for NGS library preparation and all kits give good quality cDNA uniformed in viral sequence coverage. Results of this report are useful for applicative scientists who work on SARS-CoV-2 whole-genome sequencing to compare and apply good laboratory practice for optimal preparation of the NGS library.