Antigen detection is a method for rapid detection of COVID-19 antigen. It is to mark polyclonal antibodies against COVID-19 protein on test strips to detect COVID-19 antigen in samples< br> Compared to nucleic acid testing, antigen testing has two advantages. The first is convenience. The rapid antigen detection kit is similar to a pregnancy test stick, which can be done at home without relying on complex equipment like nucleic acid testing; The second is speed. Nucleic acid testing takes at least 4-6 hours, while antigen testing only takes 10-20 minutes to produce results, which can be taken immediately< br> Before antigen self testing, the self tester should wash their hands with running water, blow their nose with toilet paper, open the outer packaging of the nasal swab, and avoid touching the swab head with their hands. Then tilt your head slightly, hold the tail of the swab with one hand and insert it into one nostril. Slowly penetrate 1-1.5 centimeters backwards along the bottom of the lower nasal passage and rotate it at least 4 times (stay for no less than 15 seconds), then repeat the same operation on the other nostril using the same swab. Individuals aged 2-14 who undergo self-examination should be sampled by an adult on their behalf, and the sample should be taken along the bottom of the lower nasal passage and inserted 1 centimeter backwards. Note that the entry into the nose should be slightly shallow at this point, and other procedures are the same< br> Immediately place the nasal swab after sample collection into the sampling tube. The swab head should be rotated and mixed in the preservation solution for at least 30 seconds. At the same time, squeeze the swab head at least 5 times by hand through the outer wall of the sampling tube to ensure that the sample is fully washed out of the sampling tube. Squeeze the liquid from the swab head through the outer wall of the sampling tube by hand and discard the swab< br> After covering the sampling tube, drop the liquid vertically into the sample hole of the detection card and wait for a certain period of time before interpreting the results. Positive results: Both "C" and "T" show red or purple bands, and the color of the band at "T" can be dark or light, both of which are positive results. Negative result: A red or purple band is displayed at "C", and no band is displayed at "T". Invalid result: No red or purple band is displayed at "C", regardless of whether a band is displayed at "T". The result is invalid, and a new test strip needs to be taken for retesting.