A red patch on the New Crown Antigen test may be due to damage to the test paper or other conditions, the results of this test are inaccurate and of no reference value, it is recommended that the test be repeated. Under normal circumstances, there are three possible scenarios for the new crown antigen test, one is that no band is shown, the second is that there is a band at c, and the third is that there is a band at c and t. The above three results correspond to invalid, negative, and positive tests respectively. These three test results correspond to invalid test, negative test, and positive test, respectively. When a red color appears on the antigen test, it is a special abnormality, which may be due to a problem with the reagents in the test paper, etc., that occurred at the factory. In this case, it is not possible to determine the test result, and it is recommended that the test be repeated, and the test result will be meaningful only if there is a clear band at position c.