Antigen testing usually refers to novel coronavirus antigen testing, which is generally not valid for more than 30 min. Before performing antigen testing, hands should be sterilized. Remove the sample extraction solution, test card, instructions, swab, sample extraction tube and other components of the antigen test kit in turn. The instructions can be referred to for subsequent operations. First, the sample extraction solution should be poured into the sample extraction tube, then the swab should be taken out with the head raised backward, and the swab should be pushed slowly along the inner wall of the nasal cavity until the swab head cannot be seen, and then the swab should be rotated for sampling. If resistance is felt, avoid forcing the swab and try the other side or change to a pharyngeal swab. At the end of sampling, dip the swab into the extract and rotate the swab for 15 seconds while squeezing. A few drops of the extract are taken onto the test card and the result is usually judged after 10-15 minutes. Two bars are positive, indicating novel coronavirus infection. One bar is negative, indicating no novel coronavirus infection. If there is no result, the test is invalid and a new test is needed. If the test takes more than 30 minutes, the result is invalid.