The antigen test is generally referred to as the New Crown Pneumonia Antigen Test. The presence of a single red line on the antigen test has no special significance and retesting is recommended. When an antigen test is performed, if there is a line at both “C” and “T”, it is positive and should be reported immediately to the community and further nucleic acid testing should be performed according to regulations. If there is only one line in the “C” position, the test is negative, and if there is only one line in the “T” position, the test is invalid. For the antigen test appears a bar of the whole piece of red situation, is likely to be due to the test paper in the production process problems or test operation process is not appropriate, waiting time is too long, etc., in general, there is no special significance, it is recommended to re-test, or immediately contact the community to explain the relevant situation, in the guidance of professionals to carry out the relevant tests. Tip: “New coronavirus pneumonia and new coronavirus pneumonia” mentioned in this article were renamed to “new coronavirus infection” on December 26, 2022, as announced by the National Health Commission.