New crown test strips (New Crown Antigen Self Test Strips) that show 2 bars after being left in place for 1 hour are not diagnostic of a positive New Crown, and are most likely due to being left in place for too long. New crown antigen self-testing paper has a time limit for observation, and the maximum time for reading the paper should not exceed 30 minutes. The typical reading time is 15 to 20 minutes. If the reading time is too long, it can be misdiagnosed due to the reaction with certain substances in the air. The presence of 2 bars on the test paper is usually positive, but because it has been left for too long, the result cannot be used as a reagent result. It is recommended that patients carry out the antigen self-test again or go directly to the hospital for nucleic acid testing, and once any discomfort occurs, go to the hospital in time for treatment and report it to avoid adverse consequences.