Antigen test for a long time become two bars, for the C line and T line, is likely to be left too long caused by the test results are generally inaccurate, it is recommended to re-open the antigen test. When using antigen test reagents, you need to read the instructions carefully and follow the corresponding requirements. Generally, the reading time is 15~30 minutes after the sample is added, and the specific time should be strictly according to the instructions. If the test result is only colored at T, it is negative. If the antigen test takes longer than the instructions and two bars appear, it may be caused by substances in the air or other reasons. There is no need to panic in the case of two bars, you can go to the hospital for testing or take the reagents at home to test again, usually still based on the nucleic acid tested in the hospital. If the test is performed according to the instructions and there are still two bars, you need to report it to the local immunization department immediately and cooperate with them according to the local regulations.