The overall reddish coloration of the antigen test may be caused by the expiration date of the reagent or an error in the test operation. If the reagent kit has exceeded the expiration date, there may be deterioration, and then go to the test may appear antigen test paper appears overall red phenomenon. In addition, if you do not strictly follow the instructions to carry out the relevant operations, the operating steps are wrong or error, may also lead to the overall red phenomenon. If the antigen kit has been placed in the air for too long, there may be some related reactions, which may also lead to the reddening of the test paper, if the overall reddening of the test paper occurs, it is recommended that the test paper be reopened or go to the hospital for further examination.