Acute pharyngitis is frequently seen in primary care
. Acute viral pharyngitis may be easily misdiagnosed as acute bacterial pharyngitis. Laboratory-confirmed diagnosis of respiratory viruses is recommended. However, few studies focusing on respiratory virus detection in adults have been conducted
. Data on the comparison of different sampling methods for respiratory virus detection in adults with acute viral pharyngitis are rare.
This study compared the sensitivities among NPS, OPS, and NW. To exclude patients with bacterial infection and increase the viral detection rate, only patients with a McIsaac score of ≤1 participated in the study. Because NPS followed by NW in the same nostril may reduce the number of cells collected by NW and reduce the sensitivity of the assay, NPS and NW were performed in different nostrils
. TaqMan real-time PCR was used to detect common respiratory viruses. In the past, viral culture was considered the “gold standard” method for viral detection, but the turnaround time of traditional culture is generally too long to be clinically feasible
. PCR offers both a substantially higher test sensitivity and a more rapid turnaround time
A variety of sample collection techniques are used to detect respiratory viruses, including NPS, OPS, nasal aspiration, NW, nasal swab, and sputa and saliva evaluation. NW and aspiration have generally been considered to be superior to swab specimen evaluation for the detection of respiratory viruses
[13, 23–25]. On the contrary, a study by Patrick et al. found that NPS had a higher sensitivity than NW for detection of viruses by real-time PCR in children
. In addition, a study by Agoritsas et al. showed that NPS and nasal swab were superior to nasopharyngeal wash for rapid immunoassay, and that both can be recommended as alternative collection methods to nasopharyngeal wash
In previous studies, many authors have used different collection methods to identify EV (throat swab)
, HMPV (nasal swab)
, rhinovirus (nasal and throat swab)
, influenza (throat and nasal swab)
, and RSV (nasopharyngeal aspirate and nasal swab)
. Moreover, Moës et al. used bronchoalveolar lavage, pharyngeal swabs, nasopharyngeal aspirates, and sputum samples for the identification of coronavirus, although the study did not aim to compare the efficacy of sampling methods
. In some clinical studies, two or more virus types were detected by different sampling methods; for example, throat swabs
, nasopharyngeal aspirates
, or nasal swabs
. So far, the differences in the efficacy of various sampling methods are unclear. The paucity of this type of study among the adult population indicates that the same sampling methods have lower sensitivities for adults than for children and adolescents
[36, 37]. Furthermore, different sampling methods can affect the results of laboratory testing.
Our findings demonstrated that NPS yielded the highest sensitivity among the three sampling methods. For rhinovirus, NPS had a statistically higher sensitivity than NW and OPS. For adenovirus, NPS had a statistically higher sensitivity than NW. In contrast, NW and OPS produced lower sensitivities of viral detection. The prevalence of influenza virus, EV, RSV, PIV, and HMPV was lower than that of rhinovirus. Although our study was not able to compare the differences among these viruses, the order of the sensitivities tended to be the same in the majority of and in the total viruses. A larger sample size may be needed to determine the significance of these differences. In addition, the study was conducted during a whole year comprising different seasons, which experienced the low influenza disease activity in Guangzhou. The seasonality of coronavirus and adenovirus was similar to that in the previous year in China
[38–40]. Furthermore, our results are consistent with the finding of Munywoki et al., who showed that nasopharyngeal flocked swab was significantly more sensitive than NW collection for detection of viruses by real-time multiplexed PCR in pediatric patients
. Therefore, the data in this study are informative and provide a reference for appropriate collection methods, particularly in subtropical cities.
The choice of a specimen should be based on the efficiency of viral detection, cost, and available expertise. For all viruses detected in the present study, NPS yielded the highest sensitivity. Moreover, compared with NW, NPS is less invasive and more acceptable to patients. NPS can be easily implemented in physicians’ clinics or emergency rooms because the collection process is rapid, little training of personnel is needed, and no special instrumentation is required
This study has a limitation. The NPS material was different from the OPS material. Studies have demonstrated that the flocked swab design yields significantly more total respiratory epithelial cells and more infected respiratory epithelial cells than does the conventional rayon swab; it also provides adequate numbers of respiratory epithelial cells for diagnosis, whether using oropharyngeal samples or nasopharyngeal samples
[41–44]. Nasopharyngeal samples reportedly have advantages over oropharyngeal samples for the identification of common respiratory viruses
[25, 45]. In China, the collection of oropharyngeal samples is mainly performed using the conventional rayon swab. Because of the relatively higher cost of the rayon swab, the flocked swab is seldom used to obtain nasopharyngeal samples. Therefore, oropharyngeal samples were obtained using rayon swabs and nasopharyngeal samples were obtained using flocked swabs in our study.