IMDX SARS-CoV2 Multiplex ORF1ab/N Gene RTPCR assay
IMDX SARS-CoV2 Multiplex ORF1ab/N Gene RTPCR assay is a real-time polymerase chain reaction (RT-PCR) test intended for the qualitative detection of SARS-CoV-2 nucleic acid, in upper respiratory specimens (such as nasopharyngeal and oropharyngeal) from individuals of human origin. The SARS-CoV-2 specific primer and probe sets in the assay are designed for the detection of ORF1ab gene and N gene, along with RNaseP gene as the human Internal control (IC) in a single tube assay.
This made in India assay is manufactured at state-of-the-art Molecular diagnostics manufacturing plant at Siemens Healthcare Private Limited, Vadodara, Gujarat. Assay is designed and developed jointly by Siemens Healthineers India & CSIR-Institute of genomics and integrative biology (IGIB) -New Delhi, after deep genomics analysis from more than 45k Genomics sequences samples & their invariant regions, resulting detection of most variants and lineages Variant of Concern (VOC) & Variant of Interest (VOI) of SARS CoV2.
Key features
- Kit comprised of a single-well dual target assay for the specific detection of SARS-CoV-2 (COVID-19)
- Test has 100% sensitivity and 100% specificity
- Covers highly conserved regions within ORF1ab and N gene identified by analyzing over 45K SARS-CoV2 genomes
- The pool of primers is designed to target regions of the virus that are unlikely to undergo mutation, allowing it to detect current and any new emerging variants.
- Approved by various regulatory bodies in India such as Indian council of Medical Research (ICMR) and Central Drugs Standard Control Organization (CDSCO)
Assay designing
High throughput genome analysis driven target selection for designing RT-PCR kit enabled prediction of invariant sites in the SARS-CoV2 genomes. Highly conserved invariant regions in ORF1ab and N gene were predicted from a genome analysis data from ICMR.
Inclusivity
The IMDX SARS-CoV2 Multiplex ORF1ab/N Gene RTPCR assay demonstrates excellent inclusivity based on a comprehensive in silico study.
Since SARS-CoV-2 was first identified in China in December 2019, the COVID-19 pandemic has spread across the globe. This spread has led to an accumulation of mutations in the viral genome. It is very important that RT-PCR assays are able to detect circulating strains, including any emergent variants. IMDX SARS-CoV-2 targets the highly conserved invariant ORF1ab region and the N gene to minimize the potential for not being able to detect new mutations, variants, and strains of the virus. Our inhouse R&D in-silico data predicted that The IMDX SARS-CoV2 Multiplex ORF1ab/N Gene RTPCR could detect all known SARS-CoV2 variants including delta and omicron.
Assay Performance
IMDX SARS-CoV-2 Multiplex ORF1ab/N Gene RTPCR Assay
Cross reactivity with other organisms
Bioinformatic analysis of ORF1ab and N primers and probe, the cross reactivity across is not identified across multiple close microorganisms as mentioned below.
The Science
Smart selection of the primer and probes
SARS-CoV2 virus is rapidly evolving, and its mutation rate is very high. So far, many variants of SARS-CoV2 have been identified with varied infectivity and pathogenicity due to accumulation of new mutations. Sometimes these new mutations fall in the region of primer-probe binding sites- reagents used for detection of SARS-CoV2 via RT-PCR. If any of these mutations overlap with primer-probe binding sites, it may influence the sensitivity of the assay.
Taking leads from this knowledge, we analyzed data given in an earlier paper published by CSIR-Institute of genomics and integrative biology (IGIB) on over 45K publicly available SARS-CoV2 genomes to identify invariant sites. Invariant sites are those regions in the genome which has not been mutated so far. We employed customized bioinformatic analysis pipeline to detected invariant sites with least probability of carrying any mutations and designed smart and highly specific primer and probes on ORF1ab and N gene. Our internal clinical data showed that this kit can COVID irrespective of infection caused by any SARS-CoV2 variant detected so far.
The Scale
The IMDX SARS-CoV-2 Multiplex ORF1ab/N Gene RTPCR Assay enables accurate SARS-CoV2 virus testing on a large scale for both reference laboratories and acute care settings. The assay produces results rapidly—in as few as 75 minutes on all the popularly used RT-PCR instruments.