Nasopharyngeal (NP) aspirates are considered more sensitive to detect viruses than traditional swabbing of the nasopharynx but they are more difficult to collect. Comparison of two methods of collection, one utilizing a new type of swab (flocked swab) to collect NP secretions and the other using the current standard, NP aspiration. Study included comparison of detection of viruses by immunochromatographic assays, direct fluorescent antibody tests (DFA), and R-Mix cell culture and to assess cost and carbon footprint of the two methods.
Dual samples were obtained from patients. The first sample (the NP swab) was taken from one nostril; the aspirate taken from the other nostril.
Considering all test methods on 106 samples, 67 positive results were detected by swab; 60 were detected by aspirate (p = 0.0455). For immunoassays for RSV, 25 were detected by swab; 21 by aspirate; for immunoassays for Influenza A/B, 10 were detected by swab; 4 by aspirate (p = 0.0039 for the combined immunoassays). For DFA, 8 were detected by swab; 7 by aspirate (p = 0.3173). For culture, 24 were detected by swab; 28 by aspirate (p = 0.1025). On a 1–4 scale, average estimation of epithelial cells retrieved with swabs was 3.6; for aspirates, it was 3.0. Cost of equipment/time for the swab method was 58% lower than aspiration. Healthcare personnel preferred swab collection. Carbon footprint of swabs was < 5% than that of aspirates.
Flocked swabs a) are statistically significantly superior for overall viral detection, b) recovered more epithelial cells, c) are preferred by healthcare workers, d) cost 58% less and e) are significantly better environmentally than NP aspiration.
Samples collected by NP flocked swabs had a statistically higher rate of positive results for respiratory viruses for the viral tests performed than did samples collected by NP aspiration.Flocked swabs may be a better alternative than NP aspiration.
Gaurav Sangwan, Other This study was funded in part by Copan Diagnostics and Diagnostic Hybrids, Inc; No Product/Research Disclosure Information