In the diagnosis of novel coronavirus infection, the collection of nasopharyngeal swabs for nucleic acid testing is an important test. The collection of respiratory mucosal surface specimens using nasopharyngeal swabs is a common clinical operation used to assess the presence of respiratory viral or bacterial infections in adults and children, considering that nasopharyngeal swab collection is a common clinical operation and is important for the diagnosis of respiratory infections, and the factors affecting the collection process There are many factors affecting the collection process, and if the operation is not standardized, it will directly affect the test results and even lead to clinical leakage and misdiagnosis. And irregular operation also increases the risk of exposure to infection for medical personnel. For patients without special contraindications to nasopharyngeal swab collection are allowed to operate, clinicians should be cautious if the patient has a recent history of nasal trauma or surgery, or has a significant deviation of the nasal septum, or a history of chronic nasal obstruction and severe coagulation disorders.

All patients undergoing novel coronavirus testing should wear a mask. Collection personnel should use appropriate personal protection as required.

Before collecting the specimen, ask the patient to remove the mask and blow the nose with a tissue to remove excess nasal secretions.

Remove the swab from the package and have the patient's head tilted back slightly to allow the swab to pass more easily through the nasal cavity to the nasopharynx. The patient is asked to close the eyes to alleviate the slight discomfort of the procedure.

Gently insert the pharyngeal swab along the nasal septum until a sensation of resistance indicates that the swab has reached the base of the nasopharynx.

Note that the pharyngeal swab should remain parallel to the palate during insertion, and if resistance is encountered as the swab passes through the nasal tract, back off the swab and attempt to re-enter at a different angle.

The insertion depth of the swab should be equal to the distance from the nostril to the external opening of the ear. The Centers for Disease Control and Prevention (CDC) recommends that the swab should be left in place for a few seconds after reaching the base of the nasopharynx to allow the tip of the swab to absorb the secretion, and then slowly removed while rotating the swab.

Handling the specimen

Open the sampling tube and insert the swab into the sampling tube. Depending on the swab, some swabs will need to be broken from the groove, and some will require placement in the original package.

Key Notes

Most respiratory viruses replicate primarily in the ciliated columnar epithelial cell sites of the posterior nasopharynx, and the ciliated epithelial cells of the anterior nostril and oropharynx, which are also the sites of most viral replication.

Therefore, the collection of pharyngeal swabs usually includes nasopharyngeal swabs and oropharyngeal swabs, and the pathogen detection rate of nasopharyngeal swabs is higher than that of oropharyngeal swabs (but this is based on the premise that nasopharyngeal swabs can be performed properly and standardized), so nasopharyngeal swabs are generally recommended.

Nasopharyngeal swabs can be tested for antigens, nucleic acids, or bacterial cultures (e.g., pertussis), but because the requirements for nasopharyngeal swabs are higher than those for oropharyngeal swabs, they are not actually given clinical attention.

Key points to note during the collection of nasopharyngeal swabs are as follows.

1. the patient needs to blow his nose first

The video requires that the patient needs to clear the nasal secretions, so first blow the nose (this step is important!!!). .

This will reduce contamination and interference with nasal secretions and ensure the quality of the specimen. 2.

2. The direction of swab entry needs to be parallel to the epiglottis

When performing the procedure, the tip of the pharyngeal swab needs to be directed toward the earlobe, not toward the top of the head.

However, in clinical practice, when taking specimens, many beginners put the tip of the pharyngeal swab towards the top of the head. Since bacteria and viruses are mostly parasitized in the bottom of the nasopharynx, if the nasopharyngeal swab enters in the wrong direction, it is difficult to reach the bottom of the nasopharynx, and the positive rate will be significantly reduced.

3. The entry depth of nasopharyngeal swab should reach the bottom of nasopharynx

The entry depth of pharyngeal swab is equivalent to the distance from the tip of the nose to the earlobe. If the tip of the pharyngeal swab is facing the top of the head in practice, the entry depth of the pharyngeal swab will be significantly insufficient.

4. No forceful and violent insertion

If the pharyngeal swab encounters resistance in the process of entering along the earlobe, it is necessary to adjust the direction and rotate slightly to enter rather than forcibly and violently inserting to avoid injury. It is enough to reach the bottom of the nasopharynx with a wall of resistance.

5. When the feeling of hitting the wall appears, the swab stays for a few seconds to rotate and withdraw (no turning back until hitting the wall)

The sensation of hitting the wall indicates that the nasopharyngeal swab has reached the bottom of the nasopharynx, so it is necessary to keep the nasopharyngeal swab at the bottom of the nasopharynx for 10-15 seconds to allow the swab to fully contact the secretions at the bottom of the nasopharynx and absorb more pathogens.

Of course, it would be more effective to follow the operation specification of rotating the swab a few times during the dwell time, but in the case of children, due to the difficulty of cooperation, it is usually required to keep the swab at the bottom of the nasopharynx for a few seconds without rotating it (although theoretically the longer the dwell time the better, and rotating it a few times is better), and then withdraw the swab while rotating it.

This reduces the irritation to the child and is equally sufficient to meet the extraction effect.