Production | Tiger Sniff Technology Group p>
Author | Shi Xuxu p>
Cover from the Internet p>
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February 7, the 6th day of Tang Moumou’s suspected case of new coronary pneumonia in Ziyang, Sichuan. She started to cough and had flaky shadows in her lungs. During the quarantine, she underwent eight nucleic acid tests one after the other and all were negative. Strangely enough, from the perspective of lung imaging and clinical symptoms, its characterization has not diminished.
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On February 24th, on the 23rd day of the quarantine, she did the ninth nucleic acid test. The result was positive and she was finally diagnosed. p>
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Tang Moumou’s experience is not an individual case. Frequent “false negative” cases are questionable, and nucleic acid testing, which has always been regarded as the gold standard for the diagnosis of new coronary pneumonia, does not seem to be so smart. p>
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Every time it takes 4 to 6 hours for the detection of New Coronavirus nucleic acid. In the case of a large number of suspected patients and asymptomatic infections still to be investigated, the diagnosis efficiency is particularly low, and the entire process has added more infections to medical staff. risk. p>
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Absolutely, antibody tests that can efficiently perform complementary diagnostics were born. strong> p>
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Recently, the China Drug Administration approved two colloidal gold antibody detection reagents from two companies, namely Wanfu Biological New Coronavirus (2019-nCoV) Antibody Detection Kit (colloidal gold method) and Innotec Biotechnology 2019-new coronavirus IgM / IgG combined detection kit (colloidal gold method). p>
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According to the introduction, both products can realize the qualitative detection of neogranulovirus IgM / IgG antibodies in human blood in vitro, and the results can be obtained in 15 minutes. strong> p>
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And compared to nucleic acid detection, antibody detection can advance the diagnostic time. p>
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“These two kits can detect IgM antibodies on the 7th day of the infection or the 3rd day of the disease, which is very helpful for the further diagnosis of the patient.” Zhong Nanshan said. p>
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20 times faster detection speed p>
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A complete set of nucleic acid detection procedures mainly includes the steps of sampling, preservation, sample inactivation, nucleic acid extraction, reagent reaction, and fluorescent PCR nucleic acid detection. p>
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The whole process of nucleic acid detection of New Crown virus in Changning District Center for Disease Control, Shanghai / Source: Xinhua News Agency p>
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The samples of New Coronavirus nucleic acid detection are collected from throat swabs. Medical staff use sterile test paper to wipe the tonsils and throat wall of the recipient’s eyes 5 to 10 times, and then immerse the samples in the cell preservation solution to save samples. Sealed and sent to the laboratory for testing. p>
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According to the requirements of the National Health and Construction Commission, samples must be inactivated at 56 ° C for 30 minutes before extraction of nucleic acids. The inactivated viral protein no longer has physiological activity and loses its pathogenic capacity, but does not affect its RNA expression. p>
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After inactivation, the laboratory extracts the nucleic acid from the sample by using a nucleic acid extractor. According to Peng Jing, a doctor of molecular diagnostics and genetics from Tongji Hospital of Huazhong University of Science and Technology, told CCTV News, This step takes 70 ~ 80 minutes, and the last step of amplification and detection of viral genes takes 1.5 ~ 2 hours strong>. p>
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This also means that, excluding the time for preliminary sampling and sample transportation, it takes 4-6 hours for a sample to be sent to the laboratory to obtain the test results. Every step from sampling to inactivation increases the risk of infection for medical personnel. p>
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The antibody test can control the test time to 15 minutes. strong> p>
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Antibodies are immunoglobulins produced by effector B cells in the immune system and capable of binding to pathogenic microorganisms after virus invasion. Weibo ID Concord Doctor Do, liken specific antibodies to precisely attack invading viruses. “Patriot Missile”. p>
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As a result, antibodies can be detected in the body, both in patients who are infected with the virus and in people who have been infected with the virus, even if they have been cured. p>
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At present, antibody detection is generally performed by the colloidal gold method, which couples colloidal gold particles with many proteins, including antigens and antibodies, to mark the IgM antibodies produced by the human body at the beginning of the infection and disappear quickly, and the long-term growth Effective IgG antibody. The sample is from blood and is less difficult to sample than a throat swab. p>
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This is how HIV is detected. It can be seen that antibody detection has a strong grasp on the virus. strong> p>
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Since the outbreak of new crown pneumonia,