A Nasopharyngeal Swab Specimen: How to Perform?

The diagnosis of COVID-19 is essential for detecting and isolating the active and asymptomatic cases to direct the treatment, and for filiation, and thereby to control the pandemic. The accurate diagnosis of COVID-19 involves collecting the correct specimen with the proper method. In a study involving 1,014 patients, while 88% of patients had positive chest computerized tomography scans, only 59% of them had positive polymerase chain reaction (PCR) results [1]. Additionally, it was also reported that although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ribonucleic acid (RNA) was detected in 63% of nasopharyngeal swabs, only 32% of oropharyngeal swabs were positive [2]. After then, the World Health Organization has recommended collecting upper respiratory specimens with nasopharyngeal swabs [3].

The diagnosis of COVID-19 is essential for detecting and isolating the active and asymptomatic cases to direct the treatment, and for filiation, and thereby to control the pandemic. The accurate diagnosis of COVID-19 involves collecting the correct specimen with the proper method. In a study involving 1,014 patients, while 88% of patients had positive chest computerized tomography scans, only 59% of them had positive polymerase chain reaction (PCR) results [1]. Additionally, it was also reported that although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ribonucleic acid (RNA) was detected in 63% of nasopharyngeal swabs, only 32% of oropharyngeal swabs were positive [2]. After then, the World Health Organization has recommended collecting upper respiratory specimens with nasopharyngeal swabs [3].
Nasopharyngeal swab specimens are easy to collect; however, an evident COVID-19 infection can be missed for several reasons, including incorrect timing and improper method of obtaining a sample [4]. Therefore, testing specimens repeatedly and from multiple sites in patients who are strongly suspected with COVID-19 infection according to clinical and radiological findings is recommended [2,4,5]. This situation shows a close relationship with the expertise and training of the medical professional who is performing the procedure. During the COVID-19 outbreak, most of the medical staff have been assigned from various departments to other wards which they are unfamiliar, to ensure personnel support. Nevertheless, the physicians, except for otolaryngologists who collect nasopharyngeal swab, may not have sufficient information about nasal anatomy. Thus, numerous illustrations and videos have been suggested to help non-otolaryngologist physicians [6].
During sample obtaining, personal protective equipment such as N95, PFF2 or masks with a higher level of protection, eye protection or face shield, long-sleeved gowns, and gloves should be used [7]. To our practice, the easiest way to obtain a sample is to insert the swab into the nasal cavity and gently direct it to nasopharynx from below the inferior turbinate along nasal floor (Figure 1). This technique has already been used by otolaryngologists during some procedures such as nasal endoscopy, nasal packing and nasogastric tube inser-

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Recently, anosmia has been described as a frequent symptom of COVID-19. Post-viral infection olfactory loss is a wellknown symptom, usually resolving within a few days, while the mean duration of COVID-19 related anosmia has been reported as nine days [8]. COVID-19 is an infection primarily manifesting respiratory system; however, neurologic component of the disease has already been described [9]. By following these findings, the reason for anosmia can be related to the affinity of the virus to the olfactory epithelium rich for olfactory nerve endings. Accordingly, if the nasopharyngeal swab is negative for SARS-CoV-2 RNA in clinically suspected patients with anosmia, as an option, the following specimen can be obtained from olfactory area and superior turbinate.

Authors' Contributions
All the authors contributed equally.

Sources of Funding
No financial supporter of this study.

Conflicts of Interest
The authors declare that they have no conflict of interest.