There is no difference in essence between the methods of collecting specimens using oropharyngeal swabs and nasopharyngeal swabs if they are operated according to specifications, both are designed to collect specimens for nucleic acid testing of neovirus to determine whether the sampled person is infected with neocoronavirus.
In order to collect the pharyngeal specimen, one is to collect the oropharyngeal specimen by passing the sampling tool through the oral cavity, one is to collect the oropharyngeal specimen by passing the sampling swab through the oral cavity, and one is to collect the nasopharyngeal specimen by passing the sampling swab through the nasal cavity. Therefore, they are referred to as oropharyngeal swabs and nasopharyngeal swabs, respectively.
When collecting samples from oropharyngeal swabs, the sampler is able to see all the sampled pharyngeal locations, but the irritation of the oropharyngeal mucosa is greater, which may lead to reactions such as coughing, nausea, or even vomiting in the sampled person. In contrast, when collecting samples from nasopharyngeal swabs, the irritation to the nasopharyngeal mucosa is relatively small, but the sampler cannot see the location of the sampled pharynx and relies mainly on the resistance felt by the hand to complete the sampling.
Compared with nasopharyngeal swabs, oropharyngeal swab sampling is sometimes more difficult to achieve normative sampling requirements because of irritant reactions. In addition, the virus enrichment in the oropharynx can be reduced to some extent due to our eating, drinking and swallowing actions, resulting in a lower positive detection rate of oropharyngeal swabs than nasopharyngeal swabs. In actual observation and comparison, the positive detection rate of nasopharyngeal swabs was also found to be lower than that of nasopharyngeal swabs. In actual observation and comparison, the positive detection rate of nasopharyngeal swabs was also found to be higher than that of oropharyngeal swabs
Of course, there are other factors that affect the positive detection rate of samples, such as the timing of sampling, usually the positive detection rate of specimens collected within a week after the onset of the disease, and more than 10 days later, the detection rate will be reduced due to the decrease in the concentration of virus-containing cells in the pharynx, there is generally no need to conduct both kinds of sampling.
