A negative antigen and a positive nucleic acid test may be a false positive or false negative due to inaccurate results from either test. Both antigen and nucleic acid tests are used to detect the presence of Neocoronavirus in the body. Antigen testing utilizes the principle of specific binding of antigen and antibody to detect the level of surface antigen of NeoCoronavirus in the body. Nucleic acid test mainly utilizes the principle of nucleic acid specific amplification to specifically amplify the RNA of the new coronavirus in the body. Due to the different principles of the two tests, there are differences in their accuracy. In general, the nucleic acid test is more accurate and reliable. When antigen is negative but nucleic acid is positive, it may be due to false-negative antigen test (higher probability) or false-positive nucleic acid test (lower probability), in which case it is recommended to repeat nucleic acid test to confirm the result.