Why are some samples taken from the nasal cavity and some from the oral cavity for the detection of new coronavirus nucleic acid? What are the differences between the two methods?
What are the methods of nucleic acid sampling?
Nucleic acid samples collected through the nasal cavity are called "nasopharyngeal swabs", and samples collected through the oral cavity are called "oropharyngeal swabs". Both are currently the main methods of collecting samples for nucleic acid testing. In addition, there are deep cough sputum, nasopharyngeal or respiratory tract aspiration, bronchial lavage, and alveolar lavage.
How to choose between nasopharyngeal swab and oropharyngeal swab?
Whether to choose a nasopharyngeal swab or an oropharyngeal swab is mainly based on the following principles: First, according to the eighth edition of the prevention and control plan and the second edition of the new coronavirus nucleic acid detection work manual, it is required that the nasopharyngeal swab should be collected first when collecting nucleic acid samples. When nasopharyngeal swabs cannot be collected, oropharyngeal swabs can be collected; secondly, nasopharyngeal swabs should be collected during isolation and observation for asymptomatic infected persons, immigrants, and close contacts; third, because the operation of oropharyngeal swabs is relatively simple , When conducting nucleic acid testing in low-risk areas, more oropharyngeal swabs should be collected.
Why should we give priority to the collection of nasopharyngeal swabs?
Studies have shown that nasopharyngeal swabs have a higher nucleic acid detection rate than oropharyngeal swabs, because the nasopharyngeal cavity is relatively closed, and the virus is more likely to be enriched; secondly, the sampler can stand behind the patient and operate, and the patient only needs to expose the nostril , There is basically no pharyngeal reflex, the exposure risk of the sampler is lower than that of an oropharyngeal swab, and it is safer. However, whether it is an oropharyngeal swab or a nasopharyngeal swab, the key is that the collection action must be standardized, in place, and in compliance with the standards. As long as the collection is standardized, both methods can achieve the desired detection purpose.
Can people with nasal diseases take nasopharyngeal swabs?
If you have the following related medical history and risk factors, you should avoid collecting nasopharyngeal swabs and oropharyngeal swabs. Such as patients with severe allergic rhinitis, nasal deformities (such as deviated nasal septum, etc.), those with recent symptoms of nasal bleeding, those with nasal cavity surgery less than 3 months old, and those with blood diseases or long-term use of anticoagulant drugs.
What should be paid attention to during the sampling process?
1. Before going to the sampling site, bring your ID card, mobile phone, alcohol wipes and other items.
2. It is best to choose a private car or cycling, walking, etc., especially in the high-risk areas.
3. Obey the instructions and guidance of the on-site staff, wait in line in districts, and wear masks throughout the entire process, do not talk with others, and keep a safe distance of 1 meter.
4. When coughing or sneezing, cover your mouth and nose with a tissue or handkerchief. Never cover your mouth and nose with your hands directly; throw the used tissue into the trash can, and then wash your hands or wipe your hands with a wet tissue.
5. Leave the sampling point immediately after sampling and avoid staying around the sampling point.
6. Wash hands immediately after returning home, and wipe and disinfect mobile phones, ID cards and other items with alcohol wipes if necessary.
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