When doing nucleic acid sampling, it can be done through the oral cavity or nasal cavity sampling, in which through the nasal cavity sampling needs to be inserted into the nose of the nasal swab about 10 centimeters for the collection of samples, stabbing too shallow or too deep is not good. 1. Poke too shallow: the new coronavirus can be transmitted through respiratory droplets, when infected by the virus, the virus will invade the human body above the mucous membrane tissue of the nose, and a large number of reproduction. The depth of the nasal cavity of the general population is about 10 centimeters, the insertion of the position is too shallow may lead to too little sampling volume, resulting in false-negative nucleic acid test, thus affecting the accuracy of the results. 2. Stabbing too deep: the nasal mucosa is relatively fragile, rich in blood vessels, and connected with the throat and other locations, if the insertion position is too deep, it may touch the throat and other locations, which may easily cause discomfort in the throat, and even bleeding may occur.