Antigen testing is generally referred to as neococcal pneumonia antigen testing. Generally, antigen tests with a shallow t-line need to be retested. During the antigen test, attention is paid to the lines at both the “C” and “T” positions. Two lines indicate a positive test, and further nucleic acid testing is needed immediately. If there is only one line in the “C” position, it is negative. If there is only one line in the “T” position, the test is invalid and needs to be repeated. Therefore, if the t-line is shallow, the waiting time was too short or the sample was not collected properly, so the sample has not reacted sufficiently with the reagent, and it is recommended that the test be repeated. It may also be a mild infection that requires further nucleic acid testing. 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.