Self-test nucleic acid, generally refers to the antigen test of the new crown pneumonia, there is a line is not obvious, generally considered to be weak positive, may have something to do with the body’s viral load is not enough. Antigen test is generally used to test paper to test, if in the test, found two bars one dark and one light, generally considered to be weak positive caused by the test, may be with the test person infected with the virus for a short period of time, resulting in insufficient viral load of the body, so it will lead to a bar color becomes lighter. It is recommended that the tester should take the test again every few days, or go directly to the regular hospital to receive the nucleic acid test, and if the nucleic acid test is also positive, the diagnosis of virus infection can be confirmed. In addition, the test paper test can only be used for preliminary testing to screen, but can not be used for diagnosis, usually need to accept the nucleic acid test can be clearly diagnosed. 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.