How Can We Make Collecting Nasopharyngeal Swabs Better

With the evolution of the novel coronavirus, many institutions are now using nasopharyngeal swab collection for virus nucleic acid testing. This method is simple, easy to implement, and more widely applicable. It is an effective method for rapid diagnosis of respiratory virus infection or carrier status. Today, Mantacc will explore the key points to pay attention to during the collection process from an anatomical perspective, in order to improve detection quality, reduce discomfort for the population, and avoid adverse events.

First, let's understand the structure of the pharyngeal regions. The pharyngeal regions include the nasopharynx, oropharynx, and laryngopharynx. The mucous membranes of these three are continuous and all belong to the upper respiratory tract. The difference between nasopharyngeal swabs and oropharyngeal swabs is just the sampling path - oral sampling is for oropharyngeal swabs, while nasal sampling is for nasopharyngeal swabs.

Now, let's explore the secrets of the nasopharynx!

There are three bony turbinates protruding into the nasal cavity on the lateral walls of the nasal cavity, arranged in a ladder-like formation with their free edges hanging inward and downward. They are called the superior, middle, and inferior turbinates. There is a slit-like space below and outside each turbinate, called the superior, middle, and inferior nasal meatus. The common narrow space between each turbinate and the nasal septum is called the common nasal meatus. On the lateral wall of the inferior nasal meatus, near the nasopharynx, there is a superficial expansion of the posterior lateral nasal venous plexus, called the naso-nasopharyngeal venous plexus, which is a common site for posterior nasal bleeding.

Deviation of the nasal septum from the midline or irregular curvature may cause nasal dysfunction, such as nasal congestion or nosebleeds.

So what do medical staff need to pay attention to when collecting nasopharyngeal swabs?

When collecting nasal swabs, the subject needs to tilt their head back. The swab should not follow the direction of the nostril, but should be perpendicular to the face, entering through the common nasal meatus. The swab should be pressed down as much as possible, close to the floor of the nasal cavity. When it enters the nasopharynx and there is a clear feeling of 'hitting a wall', gently rotate it once and withdraw vertically. During collection, if resistance is encountered or if the subject feels significant pain, do not force entry; slightly withdraw the swab. At the same time, slightly adjust the angle in the sagittal plane and try to enter again.

When sampling the nasopharynx, the operator can stand behind and to the side of the subject to operate. There's no need to directly view the oral cavity, and generally no gag reflex occurs, so tolerance is better and the exposure risk is relatively lower. Some subjects may experience a sneezing reflex after sampling, and should immediately cover with their elbow or a tissue. A small number of subjects may experience slight nosebleeds after sampling, which usually stop on their own. If necessary, a cotton swab with adrenaline can be used to slightly constrict the bleeding site. When sampling with nasopharyngeal swabs, the swab can remain in the nasopharynx for a longer time to obtain a more adequate sample.

When sampling with pharyngeal swabs, the subject should open their mouth and make a long 'ah' sound. If necessary, a tongue depressor can be used. The swab should gently and quickly swab the lateral and posterior pharyngeal walls several times. Since oropharyngeal swabbing can be done with an open mouth, it's relatively simple and therefore more commonly used clinically. However, when sampling via the oropharynx, the operator often needs to face the subject's oral cavity directly, increasing the risk of exposure.

Studies have shown that nasal swab specimens have a higher positive rate than pharyngeal swab specimens, meaning the sensitivity of virus nucleic acid detection is higher with nasal swab sampling than with pharyngeal swabs. In clinical practice, nasal swabs should be prioritized for virus nucleic acid detection sampling. This can further reduce missed diagnoses while reducing potential viral exposure for medical staff.

As the nasal cavity and oropharynx are essential passages for breathing and swallowing, exposed to the environment, it is inevitable to contact the upper respiratory tract mucosa during nucleic acid collection. This will stimulate reflexes in the nasal cavity or pharynx, causing the subject to sneeze, cough, or retch, leading to droplets or aerosols suspended in the air, significantly increasing the risk of cross-infection. If a subject in the incubation period is unknowingly sampled, it provides both the source of infection and the transmission route, easily leading to viral infection.

For those being sampled, the issues to pay attention to are:

1. 1. Try to avoid eating for 2 hours before the nucleic acid test to prevent vomiting.
2. 2. Reduce swallowing movements during the examination and don't clear your throat.
3. 3. Before collecting nasopharyngeal swabs, the subject should inform the collector of any relevant medical history. For example, history of nasal surgery, deviated septum, blood disorders, throat diseases, or use of anticoagulant medications.
4. 4. Tilt the head back as much as possible, open the mouth and make a long 'ah' sound to help expose the pharyngeal cavity. Stimulating dry cough, nausea, or vomiting symptoms may occur; try to relax and take deep breaths.
5. 5. If you feel a tingling sensation in your nose or are about to sneeze, immediately cover with a tissue or your elbow.

Mantacc Swab Supply

Our flocked nasopharyngeal swab uses a medical-grade ABS shaft with a flocked tip design. The flocked swab is manufactured using spray and electrostatic charge methods, allowing millions of nylon fibers to adhere vertically and uniformly to the handle end. The capillary action between the nylon fibers facilitates sample collection and elution. Flocked swabs have far superior sample collection and release capabilities compared to traditional twisted swabs. They are thin, soft, and mainly used for nasopharyngeal sampling of respiratory diseases such as COVID-19, influenza A and B, respiratory syncytial virus, and mycoplasma pneumoniae.