Bringing snot out of the nose will not affect the results much as long as the correct sampling process is completed. First of all, antigen detection is an immune-based test that is easy to perform, fast and efficient. The principle of antigen detection is generally based on the principle of antibody-antigen binding, in which samples that may contain pathogens are reacted with antibodies specific to the antigen, thus obtaining more intuitive coloration or data results. In the case of the commonly used nasal swab sampling, as long as the standardized sampling steps are completed, the sample on the swab contains a certain amount of antigen, even if a small amount of nasal mucus is mixed in the sampling process, it will not affect the specific reaction between the antigen and the antibody. However, in order to ensure the stability of the test results, it is recommended to clean the inside of the nasal cavity before formal sampling. Meanwhile, the antigen test has some false positives, and its result cannot replace the nucleic acid test result. Nucleic acid testing is recommended for screening in infected areas to avoid misdiagnosis.