Is the five minutes test better? Expert: nucleic acid test is irreplaceable at present

 Is the five minutes test better? Expert: nucleic acid test is irreplaceable at present

In view of the current situation and development direction of new coronavirus detection technology in various countries, China Science Daily interviewed Huang Yanyi, a professor of Peking University and deputy director of Beijing advanced innovation center for future genetic diagnosis, as well as Wang Jianbin, a researcher of Life College of Tsinghua University. A novel coronavirus laboratory test was introduced in the May 14th Science Lecture on understanding the future.

Five minute artifact is not a new invention

It should be noted that the so-called five minutes out of results artifact is not a new invention. Long before the emergence of the new coronavirus, it was already a portable device on the market to detect influenza viruses. This instrument relies on a relatively cold amplification technology, which belongs to isothermal amplification, Huang said. China food and drug administration also approved a new coronavirus diagnostic equipment based on the principle of rapid isothermal amplification.

He further explained that the instrument could produce positive results within five minutes and negative results within ten minutes. But at present, the accuracy of this method is still less than that of nucleic acid detection.

In the report and interview, Huang Yanyi repeatedly stressed that nucleic acid detection is still irreplaceable, this technology has been repeatedly verified and optimized for more than 20 years, and its specificity and sensitivity have been proved by time. At the same time, the speed of nucleic acid detection is not slow, and a small number of samples can produce results in 30 minutes at least.

In this regard, Huang Yanyi explained that the problems of false negative nucleic acid detection in current practice are mainly caused by factors such as sampling quality and timing, operating level of laboratory personnel, quality of kit, etc., not because the technology itself is not perfect enough.

So what is the level of nucleic acid detection in China? Wang Jianbin told China Science Daily that the current nucleic acid detection methods used in various countries have some differences in the sequence location of the virus. A recent study by a South Korean scientist showed that the effectiveness of these different detection sites varied. Among them, China and the United States selected the most effective and sensitive loci.

With the rapid expansion of the epidemic, the demand for detection is also changing. When home isolation becomes normal, self sampling and self testing become very practical needs.

According to Huang Yanyi, scientists from Yale University in the United States have reported that saliva sampling is even more stable than nasopharynx swabs. Recently, Rutgers University and its subordinate testing agencies have been approved by the US drug administration to start using saliva samples for the detection of new coronavirus. They use a pipelined automation machine that can detect 10000 samples a day. The domestic West China Hospital has also published relevant reviews.

Saliva sampling is a very encouraging new method. If it is popularized, it is expected to solve many problems we faced in the past. Wang said. But he also said with a smile, we tried to get 5 ml saliva needed for sampling, which is not easy.

DNA sequencing, not just testing

At the end of January this year, Huang Yanyi, Wang Jianbin and Xie Xiaoliang, Professor of Peking University, jointly developed a new RNA sequencing method, sherry.

When we conceived the subject, the new coronavirus was still an unknown thing to humans. Wang Jianbin said, but after the development of SHERRY, it just caught up with the outbreak. Because the new coronavirus is an RNA virus, it can be sequenced easily, stably and quickly by sherry.

They worked with Chen Chen, a researcher at Ditan hospital in Beijing, to sequence more than 300 clinical samples. Due to the low quality requirement of the technology, the ideal results can be obtained from nose swab, throat swab, sputum, saliva, feces and other samples.

Wang Jianbin said that the technology will not be directly applied to clinical detection of new coronavirus for the time being, but it will help to answer a series of questions that have not been answered at present, such as why the symptoms of infected people are very different, the formation mechanism of asymptomatic infected people and Fuyang patients, etc.

At present, we have found that many samples may have different mutations in specific sites. Will these mutations affect the accuracy of detection in the future? Will it affect vaccine development and drug testing? Further research is needed. Huang Yanyi said.

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