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West China Hospital: COVID-19 Diagnosis Can Be Done in Just 10 Minutes with a Single Drop of Blood

Source:sc.china.com.cn Date:2020-04-01 11:45:25Editor:刘婷婷

The COVID-19 spread through the world. As on February 20, more than 70,000 people have been infected in China while more than 2,000 people have died. The COVID-19 is not only highly infectious, but can also hide for long in patients, making diagnosis a challenge. Current tests use throat swab sampling for diagnosis but they can lead to false results if the tests are being conducted at initial stage and virus load is low. In such cases, patients will go on to test positive after negative results initially. While sputum and alveolar lavage fluid samples can give a more accurate result, they are time-taking and require advanced equipment which makes them less feasible for use in non-hospital settings. Thus, there is an urgent need for an accurate and easy-to-use test kit which can be deployed in community or grassroots hospitals.

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The novel coronavirus 2019-nCoV nucleic acid detection kit (multiple fluorescence RT-PCR method) and the new coronavirus 2019-nCoV IgG/IgM antibody detection kit (colloidal gold method) have been successfully developed by the research team of West China Hospital at Sichuan University. The two products have entered clinical verification stage.

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The novel coronavirus 2019-nCoV nucleic acid detection kit (multiple fluorescence RT-PCR method)

Novel coronavirus ORFIab gene and N gene conserved sequence were used as target sites for multiplex fluorescent RT-PCR detection kit. Specific primers and oligonucleotide fluorescent probes were designed as target sites. High specificity detection of virus nucleic acids could exclude non-specific interference of other coronavirus strains, and the detection sensitivity reached 200 copies/ml. The product develops an innovative anti-pollution system, which effectively reduces the pollution of product aerosols. At the same time, with false virus as positive control and  human housekeeping gene as the internal standard, the detection process was monitored comprehensively, which further improved the anti-interference ability of the product.

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The novel coronavirus 2019-nCoV IgG/IgM antibody detection kit (colloidal gold method)

The novel coronavirus antibody detection kit developed by colloidal gold method was developed using immunogold gold chromatography. It can be used for qualitative detection of IgM/IgG antibodies in human serum, plasma or whole blood by serological detection, specific antigen binding principle and antigen screening. The main advantage of the product is on-site instant diagnosis (POCT), which can be used in community hospitals, schools and even families for early preliminary screening. The single card and two joint detection of IgM/IgG can effectively improve detection efficiency. Observations are done through the naked eye while a drop of serum, plasma or whole blood is used to complete all the tests within 10 minutes without any equipment. The operation is simple and suspected patients can be quickly screened, which provides an efficient screening method so schools can reopen and enterprise resume work.

At present, novel coronavirus multiplex fluorescent RT-PCR kit has tested 470 clinical samples (positive 14 cases, negative 456 cases). The IgG/IgM antibody combined detection kit has tested 40 clinical samples (positive 15 cases, negative 25 cases) and match the latest guidelines issued by the National Health Protection Committee’s Disease Prevention and Control Bureau.

Chinese doctors have explored scientific and advanced treatment methods to provide an important learning reference for the world to fight the novel coronavirus. China has also donated a novel coronavirus nucleic acid test kit to Japan.