Antigen test does not show that the test failed, may be due to the expiration of the test reagent, test reagent improper preservation, improper measurement method, measurement of environmental abnormalities, etc., need to re-test. 1. Expired test reagents: usually before the antigen test, patients need to check the date, if the shelf life is exceeded, it will affect the quality of the test preparation, which will also affect the test results, the test is invalid. 2. Improper preservation of test reagents: usually when the antigen test is not carried out, we need to pay attention to the preservation of reagents, if the reagents are missing, broken and so on, it will also affect the test results, and should be replaced in a timely manner reagents. 3. Improper measurement: Before antigen detection, you need to carefully read the instructions to understand the testing process and related precautions, if you test yourself improperly, there may also be a test failure. 4. Abnormal measurement environment: Generally, there are certain requirements for temperature and humidity when performing antigen testing, and if the test is performed in a too-cold, too-hot, or too-humid environment, it may lead to abnormal results. It is recommended to perform antigen detection correctly according to the instructions, if there is no display of antigen detection, it is necessary to re-test.