SARS-CoV-2 variants add a new layer of risk and complexity to the COVID-19 pandemic, and researchers must work to keep up with the emergence of mutations in order to design new diagnostic, therapeutic and preventative solutions. Access to synthetic RNA transcripts of the SARS-CoV-2 variants helps accelerate research and method validation and can help ensure better reproducibility for molecular assays. New external run controls now available from Bio-Rad offer the ability to monitor the performance of research assays targeting mutations in the SARS-CoV-2 Spike (S) gene, with synthetic RNA transcripts of the Alpha, Beta, Gamma and Epsilon variants.
The new variant run controls are part of the Exact Diagnostics line of molecular quality control products for research testing. The products are to be used with assays detecting SARS-CoV-2 variant RNA and can be processed in the same manner as patient specimens to monitor all the steps of molecular assays. Each control comes in a matrix simulating transport media and the product also contains human genomic DNA (human gDNA), including human RNase P, for internal control needs. This enables laboratories to monitor the entire process of an assay including extraction, amplification and detection, according to Bio-Rad. The extraction step is optional when using this product.
The SARS-CoV-2 variant S genes are internally quantitated to 200,000 copies/ML and the human gDNA is internally quantitated to 75,000 copies/ML, using the Bio-Rad Droplet Digital PCR (ddPCR) system for lot-to-lot consistency. The products have an 18-month shelf life from date of manufacture when stored at -20°C, or 12 months when stored at 2-8°C.
Bio-Rad also offers additional SARS-CoV-2 quality controls in its Exact Diagnostics line, including Delta-Kappa variant controls, a SARS-CoV-2 standard, and positive and negative run controls.