The validity period of nucleic acid test results is dynamically adjusted according to regional policies. Nucleic acid test results do not have a fixed period of time and may not be valid for seven days in all regions. Especially in some areas where there is an indigenous outbreak, it is usually valid for 48 hours, after which it loses its validity and requires a new nucleic acid test. The validity period of nucleic acid testing is a stopgap measure for control or good protection against new crowns, and it is very important to combine this with epidemiologic history. There is also a combination of the patient’s symptoms. The report of nucleic acid test only represents the status before doing the test, because the incubation period is long, need to timely review, must pay attention to the epidemiological history and the patient’s own symptoms. The specific validity period needs to consult the local CDC department, and it is recommended to actively cooperate with the local epidemic prevention policy.