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New Research Methodology for identifying SARS-CoV-2

Genesis Healthcare Co. reveals research methodology for identification and reduction of SARS-CoV-2 false negative for RT-PCT tests.

Japanese genetic testing and research company, Genesis Healthcare Co., announced in early October 2020 results of its research to identifying SARS-CoV-2 and reducing the number of false negatives for RT-PCR tests conducted in Japan.

It first introduced its RT-PCR testing services in April 2020, and has since conducted extensive research to identify and isolate false negatives of SARS-CoV-2, and recent findings have been submitted as a preprint article on 9 October 2020.

The research paper was titled, “Detecting and Isolating False Negative Of SARS-CoV-2 Primers and Probe Sets Among the Japanese Population: A Laboratory Testing Methodology and Study”.

In the research, Genesis Healthcare conducted a comparative study between primers from disease control centres of different countries. A total of 11,652 samples were from the Japanese population were tested for SARS-CoV-2 using recommended RT-PCR primers/probe sets from Japan National Institute of Infectious Disease (NIID) including JPN-N2 / JPN-N1 and US Centres for Disease Control and Prevention (CDC) including CDC-N2 / CDC-N1.

The current protocol for Japan from NIID is JPN-N2 alone, however Genesis Healthcare has included primers/probe sets from CDC-N2 and CDC-N1 for all its RT-PCR COVID-19 tests since April 2020.

Out of the 102 samples, 17 were positive (16.7% of total positives) showed inconsistent results when tested simultaneously for all the following primers: JPN-N2, JPN-N1, CDC-N1, and CDC-N2. Findings show that due to the inconsistencies in the results for JPN-N2, JPN-N1, CDC-N1, and CDC-N2 primers / probe sets, SARS-CoV-2 samples run via RT-PCR for JPN-N2 could result in false negative or positive and are subjected to differences in virus mutation in a specific sequence region targeted by a primer.

Other findings from the study demonstrated that the use of JPN-N2 primer combined with CDC-N2 primer produced the most effective result in reducing the number false negatives in the Japanese sample population. Furthermore, adding CDC-N1 also resulted in reducing false negatives and false positives.

Infectious PCR-testing requires constant review of the testing protocol for mutations and the current research finding raises the need for the international testing community to explore a standardized universal primer/probe sets combination for more accurate RT-PCR based COVID-19 testing. This could help to detect different strand’s reaction to selected primers by each country’s testing protocol. It is a critical consideration to ensure accurate diagnostic testing to ensure public health and safety while more countries are re-opening their borders and resuming international travel to sustain economic growth. [APBN]