On April 17, the Information Office of the Shanghai Municipal People's Government held a press conference on epidemic prevention and control. Gao Chunfang, director of the Laboratory Center of Yueyang Integrated Traditional Chinese and Western Medicine Hospital affiliated to Shanghai University of Traditional Chinese Medicine, said that it is necessary to repeat multiple tests at high frequency. It is also a very effective means in the current epidemic.

  First of all, any infectious disease has a certain incubation period, and the new coronavirus infection is no exception, and the incubation period varies from individual to individual.

  The second concept is the detection window period, which means that after the patient is infected with the virus, the existing detection method does not reach the detection sensitivity and cannot be detected because of the relatively low load.

The period before the test is the window period of the test. In fact, it is very easy to miss the test during the window period. Whether the positive person can be caught in time depends on the frequency of testing. The more the frequency of testing, the shorter the window period. in the shortest possible time.

  Third, because the sampling of respiratory pathogens mainly adopts several forms of throat swab, nasal swab, and nasal + pharyngeal swab, there are inevitably certain sampling differences in the sampling process.

This difference includes the sampling site, depth, and the amount of secretions collected.

Therefore, repeated sampling and testing can make up for the possible false negative effects caused by sampling errors.

  Another very important reason is that during clinical trials, not only the infection of the new coronavirus, but also the infection of other pathogens are also tested repeatedly, usually 3 to 5 times.

In this way, the detection of the new coronavirus is no exception. Repeated tests can be very effective in catching patients.

Under the current situation, repeating multiple tests can timely lock positive people, especially asymptomatic infected persons, risk areas and key groups, and isolate the source of infection, block the route of infection, and protect susceptible groups in time. .

(Making Yueziyan)

Responsible editor: [Wang Kai]