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New Research and Testing Methodology to Identify and Reduce SARS-CoV-2 False Negatives In Japan

Tokyo, October 12, 2020 – – Genesis Healthcare Co., Japan's leading genetic testing and research company, reveals a research methodology to identify and reduce SARS-CoV-2 (COVID-19) false negatives for RT-PCR tests conducted in Japan.

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

In the research titled “Detecting and Isolating False Negative Of SARS-CoV-2 Primers And Probe Sets Among The Japanese Population: A Laboratory Testing Methodology and Study”, Genesis Healthcare conducted a comparative study between primers from different countries' disease control centers. 11,652 samples from 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 Centers for Disease Control and Prevention (CDC) including CDC-N2 / CDC-N1.

The current protocol for Japan as per guidelines 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.

Of the 102 positive samples, 17 samples (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 inconsistency in the positive / negative 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 will result in false negative / positive subjected to differences in virus mutation in a specific sequence region targeted by a primer.

Further findings outcome shows that the use of JPN-N2 primer combined with CDC-N2 primer produces the most effective result to reduce false negatives in Japan region. Furthermore, adding CDC-N1 will result in reducing false negatives, but also false positives.

Infectious PCR-testing requires constant testing protocol review for mutation and the 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, which shall help to detect different strand’s reaction to selected primers by each country’s testing protocol. This is a critical consideration to ensure accurate diagnostic testing entailing public health and safety while more countries are re-opening their borders and resuming international travel to sustain economic growth.

About the Research

The article preprint is available on the health science portals of medRxiv:

About the Authors

Wataru Tsutae (11) , Wirawit Chaochaisit (1), Hideyuki Aoshima (1), Chiharu Ida (1), Shino Miyakawa (1), Hiroko Sekine (1), Afzal Sheikh (1), Iri Sato Baran (1), Toshiharu Furukawa (1) (2), Akihiro Sekine (1) (3).

(1) Genesis Institute of Genetic Research, Genesis Healthcare Corporation, Tokyo, Japan

(2) Department of Surgery, School of Medicine, Keio University, Tokyo, Japan

(3) Department of Emergency and Critical Care Medicine, Chiba University, Chiba, Japan

About Genesis Healthcare Co. Ltd

Genesis Healthcare Co., Ltd. is a leading biotech company, pioneering genetic research since 2004 and promoting preventive healthcare and wellness through genetic testing. Leveraging more than 16 years of genetic research and development, Genesis Healthcare empowers medical institutions and end consumers alike to evolve towards personalized wellness and medicine. Originated in Japan, Genesis Healthcare offers medical, corporate, and consumer services through a range of innovative services across the Asia Pacific region.

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