Smoking is not allowed 30 minutes prior to the nucleic acid test and can have an effect on the test results. If the subject smokes 30 minutes before the test, he/she needs to inform the nucleic acid testing personnel in advance and consult with the relevant personnel when the test can continue, which usually requires a delay of about half an hour. Since the novel coronavirus is a respiratory virus, the pharyngeal secretions of infected persons can contain a large amount of the new coronavirus, so nucleic acid testing is usually performed by collecting secretions from the oropharynx or nasal cavity. The harmful substances in tobacco can affect the oral or nasal environment, causing increased secretions from the mouth and throat, and manifestations such as spitting up and repeated swallowing of saliva, which can decrease the content of virus in the pharyngeal saliva and lead to false negative results of the test. In addition, to ensure the accuracy of the results, try not to eat 2 hours before the nucleic acid test, and also take care not to drink alcohol, water, chew gum, betel nut, drinks, etc. for the first 30 minutes. During the test, you should reduce swallowing movements and refrain from throat clearing, such as coughing and spitting. Waiting for the testing process need to pay attention to the whole wearing mask, remove the mask when the test, immediately after the test to wear.