How to Obtain a Nasopharyngeal Swab Specimen

To the Editor

The appropriate procedure for obtaining a nasopharyngeal swab specimen, as shown in the video by Marty et al. (published on April 17 at NEJM.org),¹ is of paramount importance. Proper collection of a specimen for virus detection, which is essential to minimize false negative results, depends on the expertise and training of the person who is performing the procedure.²

During the Covid-19 pandemic, health care workers from various hospital departments have been redirected to other departments in order to provide enough staff. Non-otolaryngologists who are assigned to collect nasopharyngeal specimens may not be familiar with nasal anatomy. To overcome the lack of anatomical knowledge and skills, various videos and illustrations have been published. However, some of them have provided the wrong directions for accessing the nasopharynx.³

Figure 1. Figure 1. Collecting a Nasopharyngeal Swab Specimen.

The nasopharyngeal swab should be inserted in the direction of the dashed line from the nasal ala to the earlobe (in line with the nasal floor) until the nasopharynx is reached. The use of these landmarks may prevent false negative samples.

We think that the most easily understandable and correct approach for this procedure is to insert the swab and direct it from the nasal ala toward the earlobe⁴; this follows the direction of the floor of the nasal fossa (Figure 1). This technique, which is used in our daily practice as otolaryngologists during nasal packing for epistaxis, may improve the quality of specimen collection, especially if nurses or other persons who are not ear, nose, and throat specialists are obtaining the sample.

Apostolos Karligkiotis, M.D.
Alberto Arosio, M.D.
Paolo Castelnuovo, M.D.
Azienda Socio Sanitaria Territoriale Sette Laghi, Varese, Italy
[email protected]

This letter was published on May 29, 2020, at NEJM.org.

To the Editor

The video by Marty et al. shows how to correctly obtain a nasopharyngeal swab specimen for the diagnosis of Covid-19. However, the specimen could have been collected more safely. First, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be transmitted by aerosols,¹ so the personal protective equipment (PPE) shown in the video is not sufficient to protect a person who is collecting the specimen. In addition to the PPE shown, a disposable hat and a piece of a medical coverall that can protect the health care worker’s neck should be used. Second, the patient should wear a mask so that only the nostrils are exposed. Third, after the collection, the health care worker should not hold the swab, since it has been contaminated by the patient’s nostrils. Finally, the hand washing of the health care worker appears to be too casual.²

Standard hygiene, adequate PPE, and careful donning and doffing of PPE are important measures to protect health care workers and patients from infections. Although some protective measures are controversial, appropriate enhanced protection may be better than no protection.³

Tao Liu, M.D., Ph.D.
Nan Li, M.D., Ph.D.
Nini Dong, B.S.N.
Chinese People’s Liberation Army Navy 971 Hospital, Qingdao, China
[email protected]

This letter was published on May 29, 2020, at NEJM.org.

To the Editor

The procedure for obtaining a nasal specimen, as shown in the video and described in the accompanying text by Marty et al., could be improved. Although it seems appropriate that patients remove their masks for nose blowing before a swab specimen is obtained, we think they should be asked to replace the mask over their mouths before nasopharyngeal swabbing to minimize the risk of release of virus into the environment if the swabbing induces coughing. Furthermore, patients should be encouraged to wash their hands or use hand sanitizer each time they manipulate their masks.

Some hospitals and clinics have had a shortage of gloves. Thus, the alternative of disinfecting gloves with an alcohol-based hand sanitizer instead of changing the gloves might be considered.

The placement of the swab specimen as shown in the video contaminated the transport bag. The bag could be arranged so that the specimen could be placed into it, and the bag could be closed only after the health care worker’s gloves have been disinfected or changed.

Finally, a head covering could be considered for health care personnel to reduce contamination. This is especially appropriate for persons with long hair.

Christy McRae-Siebenbrodt, R.N.
Hans L. Tillmann, M.D.
Christopher J. Hostler, M.D., M.P.H.
Durham Veterans Affairs Health Care System, Durham, NC
[email protected]

This letter was published on May 29, 2020, at NEJM.org.

To the Editor

The content of the video by Marty et al. was helpful for learning how to obtain a nasopharyngeal swab specimen in ordinary times. However, during the Covid-19 pandemic, PPE has been somewhat or completely limited at hospitals in many countries. For instance, in some hospitals, it has been impossible to change gloves many times. It has also been difficult to wear the appropriate PPE. It may be helpful to add information on how to save PPE while minimizing the possibility of spreading the virus.

Shigeo Fuji, M.D., Ph.D.
Osaka International Cancer Institute, Osaka, Japan
[email protected]

This letter was published on May 29, 2020, at NEJM.org.