416. Comparative Analytical Assessment of PCR Mastermixes for Detection of SARS-CoV-2 using the CDC Diagnostic Test and the LightMix Modular Test on the cobas® z 480 Analyzer

BACKGROUND: The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a betacoronavirus responsible for the ongoing global pandemic and associated respiratory disease. Rapid development and implementation of molecular diagnostic testing solutions has been imperative to meet the enormous and urgent public health needs, and remains a key component of the US emergency response. Nucleic acid amplification tests (NAATs), with emergency use authorization (EUA) by the FDA, have been subject to significant supply chain shortages. This study aims to comparatively assess several commercially available substitutive mastermix reagents for the CDC SARS-CoV-2 EUA test and the TIB Mol Biol LightMix Modular (RUO) test. METHODS: Positive control material included with each testing kit was used directly as DNA template for all manually assembled reactions and comparative evaluation. Additionally, these tests were evaluated similarly using the cobas omni Optimization kit, the first step in assessing suitability on the cobas® omni Utility Channel for high-volume user-defined molecular testing on the fully automated cobas® 6800/8800 Systems. All PCR was performed per the manufacturer’s instructions using the User Defined Workflow (UDF; open channel) on the cobas® z 480 analyzer. RESULTS: Robust amplification of the commercial control material was observed with each mastermix for all gene targets within the CDC and LightMix tests. Modest but significant (ANOVA, p< 0.05) target-specific Ct-value impacts were observed among the mastermixes assessed in this study. Using the cobas® omni optimization kit, Ct values for each target within the CDC and LightMix tests were consistently and significantly lower (ANOVA, p< 0.05) than the comparator mastermixes. CONCLUSION: Each mastermix may be a useful alternative to the recommended mastermix for SARS-CoV-2 detection. Additionally, these findings suggest the CDC and LightMix tests may be adapted for fully-automated, high-throughput testing on the 6800/8800 Systems. DISCLOSURES: Steven Cagas, PhD, Roche Diagnostics Corp (Employee) Stephen McCune, BS, Roche Diagnostics Corp (Employee) Pedro Rodriguez, Ph.D, Roche Diagnostics Corp (Employee) Ray Hein, PhD, Roche Diagnostics Corp (Employee) John Osiecki, PhD, Roche Diagnostics Corp (Employee) Nicole Robinson, Ph.D, Roche Diagnostics Corp (Employee) Chris L. McGowin, PhD, Roche Diagnostics Corp (Employee)