Antigen self-testing generally refers to the new coronavirus antigen test, put a few hours suddenly become 2 bars may be non-specific binding increased due to this time the results of the test is not accurate. Generally, the results need to be interpreted within 15-20 minutes after the new coronavirus antigen test is performed, and the results are generally more accurate when interpreted during this time. If there is a 1-bar line before the new coronavirus antigen test and then a 2-bar line a few hours later, it is likely to be due to an increase in non-specific binding of the abnormal line. Generally speaking, if 2 bars appear a few hours after a new coronavirus antigen test has been performed, the result is no longer accurate and is no longer informative, so a retest can be performed. It is recommended that the results be judged within 15-20 minutes after the new coronavirus antigen test has been performed, and that the results should not be judged outside of the prescribed time frame to avoid misclassification.