Recently, the network rumors "new crown virus nucleic acid test, half an hour to get the results", "detection of new crown, only ten minutes", "home can also do nucleic acid test" ...... for whether these contents are true, Heilongjiang Provincial Center for Disease Control and Prevention, deputy director of the Institute of Viral Disease Prevention and Control Chen Shuhong interviewed by reporters, and introduced the whole process of nucleic acid testing and the time required.

The net rumor "nucleic acid test as soon as half an hour to get the results"? Impossible

Chen Shuhong told reporters that the new coronavirus nucleic acid testing, first of all, specimen collection, followed by laboratory testing, the provincial CDC Laboratory for the prevention and control of viral diseases for the new coronavirus nucleic acid testing is based on national programs, using the method of real-time fluorescence RT-PCR. "Using this method, half an hour is not possible, it takes about 2 to 4 hours. ."

Chen Shuhong said 2 ~ 4 hours, usually understood to be simply a specimen of the operation time. According to reports, the laboratory usually carry out batch specimen operation, hundreds of specimens to the laboratory after the specimen verification, specimen finishing, specimen pre-processing and other links need 3 to 4 hours, before the real nucleic acid extraction process, nucleic acid extraction after the need for PCR amplification, also need 80 to 120 minutes.

After the PCR, the results are determined, the data is checked and the report is issued. "For our lab size, for 500 specimens, the whole process takes 8 to 10 hours."

Chen Shuhong said that the whole process, referring to the ideal laboratory operation process, means a one-time success; for difficult specimens, there is a need to repeat the test, and even the need to repeat the specimen collection, then it will take longer.

Specimen collection: three levels of protection, biosafety, a well-ventilated environment, "one of the three" is indispensable

It is understood that in the sampling site, the name, gender, age and other information to be registered, but also with the medical staff to verify proof of identity, after the sample collection.

According to reports, because the pharyngeal swab sample collection process may occur dry cough or vomiting phenomenon, so in order to protect the collector and the collected, to prevent cross-infection, the collection of personnel to do a good job of three-tier protection.

"Not only personal protection should be in place, after sampling, but also to do a good job of cleaning and disinfection of medical waste, object surfaces, ground and so on." Chen Shuhong told reporters that the sample delivery process should also pay attention to biosafety. Involving external specimens transported, should be packaged in three layers according to the type of specimen in accordance with Class A or B infectious substances.

Laboratory testing: specimen processing, nucleic acid extraction, PCR amplification, issuing reports, "four steps" all take time

After the specimens are received, the laboratory staff will organize and verify the specimens for pre-processing. "Our tests are usually batch tests, with one or two hundred samples coming in. It may take 2 to 3 hours to check the calibration of the samples first, and there are some special specimens that have to be pre-processed. Then one or two hundred specimens, it usually takes 3 to 4 hours for calibration and pre-processing.

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According to the introduction, in terms of biosafety, the process of specimen handling is very critical, and the operation of uncultured infectious material should be carried out in a biosafety level 2 laboratory, while using personal protection in a biosafety level 3 laboratory. The specimen handling process is a zero-distance contact between the laboratory personnel and the virus, and the operation should be carefully regulated.

How long does it take for nucleic acid extraction? Chen Shuhong introduced, according to the conditions of each laboratory, nucleic acid extraction time is also different. According to the standards of the provincial CDC, the time required to extract nucleic acid from 500 specimens takes about 3 to 5 hours.

After nucleic acid extraction, the final step of nucleic acid testing, PCR amplification, is usually required. This step varies slightly depending on the reagents used. "At present, we amplify the reagents from the start of the machine to the end of the machine, do a round of a machine is up to more than 90 samples, it takes about 80 to 120 minutes.

According to reports, the end of the experiment, but also to analyze the relevant data, sorting, and finally issued a test report. In the case of more samples, this link also takes several hours to complete. The entire testing process biosafety is very important, and each operational link must be very careful. "Experimenters have to go through strict biosafety training, including strict operation and proper donning and doffing of protective clothing. After the experiment, the laboratory countertop, floor and space must also be disinfected and treated, the experimental waste and protective supplies must be disinfected and sterilized, and finally the disinfected waste and waste must be transferred in a regulated manner." Chen Shuhong said.