Pharyngeal swabs do not contain chemicals, they are simply long sterile cotton swabs. The main components of the pharyngeal swab are nylon staple fibers and medical ABS (acrylonitrile-butadiene-styrene copolymer) plastic. The pharyngeal swabs do not contain other chemical components, on the one hand, to ensure the stability of the collected sample, to avoid the reaction with the collected specimen due to the presence of chemical components and to ensure the accuracy of the test. On the other hand, the collected specimen needs to be sent to PCR for amplification, and the presence of other chemicals in the process may affect the PCR reaction. Throat swabs are free of other chemicals and can be collected with confidence so that the presence of infection can be clarified in a timely manner.