SARS-CoV-2 Molecular Diagnostics Development

The highly pathogenic nature and transmission dynamics of SARS-CoV-2 have necessitated the availability of rapid, robust detection methods to ensure that infected individuals are treated in a timely manner. For SARS-CoV-2 molecular diagnostics manufacturers moving from emergency use authorization (EUA) to 510(k) premarket submission to the US Food & Drug Administration (FDA), robust testing must be performed to demonstrate that the device is safe and effective as well as substantially equivalent to legally marketed devices. To support these validation studies, ATCC provides an extensive array of authenticated and clinically relevant materials for evaluating limit of detection, inclusivity, and cross-reactivity.

Our extensive collection contains a variety of viral, bacterial, and fungal species for SARS-CoV-2 molecular diagnostics development, including SARS-CoV-2 reference materials, high-priority pathogens from the same genetic family as SARS-CoV-2, and high-priority organisms likely present in respiratory specimens. To support your unique assay development needs, we provide these materials in a variety of formats.

• Heat-inactivated preparations – Inviable, non-replicative preparations that are quantitated by Droplet Digital PCR or qPCR. These materials are ideal for use in molecular assays or as a process control (e.g., nucleic acid extraction through the qPCR amplification process).
• Live strains – Minimally passaged, fully characterized strains that are authenticated using a polyphasic approach that confirms genotype and phenotype.
• Genomic nucleic acids – Whole-genome preparations aseptically prepared from minimally passaged ATCC cultures. Each preparation is supported by stringent quality control testing to ensure product authenticity and functionality.
• Synthetic nucleic acids – Quantitative DNA and RNA synthetically manufactured under ISO 13485 guidance to include key target regions from select viral, bacterial, and protozoan species. These standards enable researchers to work with higher concentrations of target nucleic acid sequences for unculturable or high-containment species.
• Respiratory inclusivity and exclusivity panels  – ATCC’s respiratory inclusivity and exclusivity panels are composed of authenticated nucleic acids or heat-inactivated material derived from respiratory pathogens commonly cited for use as control materials in SARS-CoV-2 EUA submissions and/or FDA 510(k) submissions.

Because molecular diagnostic assays provide powerful tools for the rapid detection and identification of clinically relevant pathogens, it is essential that they are properly validated to guarantee accurate results and uncompromised data. To evaluate the performance of a novel molecular diagnostic test for SARS-CoV-2, we provide a variety of materials for validation studies on the limit of detection, inclusivity, and cross-reactivity of the assay. These studies help ensure that the assay is able to accurately detect SARS-CoV-2 without reacting to related pathogens.

• Limit of detection – The minimum amount of a target that can be accurately distinguished from the absence of a sample within a given level of confidence. For SARS-CoV-2 molecular diagnostic assays, the FDA recommends testing a quantitated inactivated viral preparation spiked into a clinical matrix as the inactivated preparation closely reflects the live virus in a clinical sample. Genomic RNA is also recommended as a material for testing.
• Inclusivity testing – Confirmation that your assay detects the intended target. Testing should include multiple strains of SARS-CoV-2 and demonstrate that the strains can be detected by the proposed assay. In silico analysis of published SARS-CoV-2 sequences is also acceptable.
• Cross-reactivity testing – Confirmation that your assay does not react with related pathogens or normal/pathogenic flora that may be present in the clinical sample. For this study, the FDA recommends testing high priority pathogens from the same genetic family and high priority organisms that are likely present in a respiratory specimen.

ATCC has developed four quantitative synthetic molecular standards for use as controls in the development of assays designed to detect and quantify SARS-CoV-2. Because these standards are synthetically derived, they eliminate the need to culture viruses in the laboratory and they are safe to use under biosafety level 1 conditions. These constructs are compatible with several assays, including the nucleocapsid-targeted real-time RT-PCR primer and probe sets developed by the CDC.