Two bars of nucleic acid-negative antigen are not necessarily an infection, and further steps such as retesting and expert panel validation are required. In the event of a negative nucleic acid test result and a two-bar antigen test, i.e., a positive result, it is not straightforward to determine that the person is infected. Antigen testing is generally used as an initial screening tool and cannot be used as a definitive diagnosis because it requires self-testing by the person being tested and the results are affected by the relatively low accuracy of the test strips. In such cases, the results of nucleic acid testing should still be used as the basis, and timely retesting of the nucleic acid test should be carried out; if the test is negative, infection can be ruled out, and if it is positive, a panel of experts is required to verify the results. Nucleic acid testing is much more sensitive for neocoronaviruses and is currently the main diagnostic criterion for neocoronavirus infection.