Self-Collection of Nasal Respiratory Tract Sampling by Volunteers Using the Copan Nasal Flocked Swabs Design
Background: Nasal swab (NS) collection for diagnosis of respiratory viruses is less invasive than nasopharyngeal swabs (NPS). In a previous study, we demonstrated that 2 newly designed flocked nasal swabs (round and flat) were essentially equivalent to NPS in sampling respiratory epithelial cells for the diagnosis of viral respiratory infections.
Objective: To asses the quality and the feasibility of self-sampled nasal swab compared to staff-collection using the Copan nasal flocked swabs design.
Methods: We enrolled 35 volunteers, each of whom self-collected two NS using the Copan new nasal flocked swab design (round and flat) with the guidance of written and illustrated instructions; followed by another two NS (round and flat collected by a physician or trained research staff. The flat swab was inserted 4-5 cm in the nostrils without rotating, the round swabs was inserted to the same distance and was rotated three tines. The order of NS type was randomized on subject’s nostril of choice. Discomfort, ease of administration, and preferences were assessed using a 5-point Likert scale. The swabs were placed in a 1.0 ml tube of Copan UTM-RT, vortexed, and centrifuged, with the residual cell pellets resuspended in 1.0 mL PBS, 25 L suspensions were placed in wells on a glass slide, dried, fixed and counter-stained with FITC-labelled monocional antibody. Respiratory epithelial cells were quantitated using a fluorescent microscope at 400x magnification by an experienced microscopist blinded to swab type while enumerating. An average count from 4 fields was calculated when 10 or more epithelial cells were present per high-powered field (hpf); 10 fields were averaged if there was fewer than 10 cells/hpf.
Results: Among the 35 subjects, the mean (SD) cell yields for round swabs were 81. (44.8) and 43.2 (38.1) for researcher- and self-administered- NS respectively (p<0.001); cell yields for flat swabs were 76.6 (45.0) and 36.0 (29.9) (P<0.001). While round NS collected more cells than flat NS, the difference was not statistically significant. However, using a widely-accepted definition of an adequate quality. Overall, both flat and round NS were well tolerated with 75% of volunteers reporting no or mild discomfort. Self-administration of NS was easy (97%) and a majority of individuals (75%) were either neutral or preferred self-collection.
Conclusions: Self-administered nasal sampling was easy, preferred, are alnost comparable to staff-collected swabs for sampling the upper respiratory tract. Clinical correlation studies with the improved self-collection flocked nasal swabs design are now in progress.