Twice a day antigen self-testing is necessary for high-risk groups. If you are in a medium to high risk area or are a close contact of a new coronavirus or a concentrated quarantine population imported from abroad, it is also necessary to do antigen self-testing twice a day to increase the detection rate of positives and to avoid under-diagnosis. For people in low-risk areas or the general population, it is generally not necessary to do antigen self-testing twice a day. This group can be screened once a week as a general screening test. If antigen self-testing is considered positive, nucleic acid testing is recommended for clarification. Antigen self-testing is only a preliminary screening test, and a definitive diagnosis depends on nucleic acids.