Nucleic acid sampling is a common method of detecting novel coronaviruses, including pharyngeal swabs and nasal swabs, with attention to three steps: pre-testing, testing and post-testing. 1. Before the test: 2 hours before the nucleic acid test should try to avoid eating, 30 minutes before the sampling, no water, no water, no smoking, reduce the swallowing action. Any history of nasal or pharyngeal surgery or blood disease before sampling should be informed in time, and the examinee should wear a mask correctly and keep a proper distance. 2. During the test: the examinee should tilt his/her head back, take a deep breath, and open his/her mouth to make the “ah” sound, so as to expose his/her throat and make it easier for the medical personnel to conduct the sampling. 3. After the test: the examinee should wear a good mask and leave the collection site in time. Before and after the test need to pay attention to personal hygiene. Nucleic acid testing is a common screening method for detecting new coronaviruses, which can effectively prevent the spread of the epidemic. Attention should be paid to order during the nucleic acid test, and leave as soon as possible after the test is done, do not linger.