The antigen test shows all red color, which means that the antigen test result is positive. This can be caused by problems with the quality of the antigen test supplies. When the artificial antibody is combined with the patient’s antigen, it will show red color in both C and T zones, and then the patient is basically diagnosed with a certain pathogen. The main principle is to use the synthetic Gal antigen (Gal-BSA) as the solid phase antigen, through the ELISA method to detect the remaining antibody in the supernatant after the first reaction; and then the standard curve can be used to calculate the content of α-Gal antigen in the test material to be measured, if the measured antigen content exceeds the sensitivity of the test paper, then the red color will appear. Antigen test consumables quality problems caused by the antigen test all show red, is a misdiagnosis of the situation, you need to re-use a new antigen test kit in accordance with the instructions for testing. If the antigen test shows red color, it is necessary to report to the hospital in time and review the test in time to make sure that the virus is not spreading.