Background: We previously developed a method for self collection of nasal swab samples and demonstrated that self-collected swabs were sensitive (sensitivity 96%) compared with staff-collected nasal washes (sensitivity 88%) for detection of respiratory viruses (RVs) by PCR in 152 collections from immunocompetent volunteers with new upper respiratory infections (URIs). Our self-collection method employed saline spray delivered by a metered spray bottle and a polyurethane foam swab, but many current protocols advocate use of dry respiratory swabs. In the present study, we compare collection of swabs with and without use of saline spray in both immunocompetent volunteers and HCT recipients. Methods: Immunocompetent volunteers with new URI completed a symptom survey and performed self collection in one naris using saline spray and a polyurethane foam swab ("wet"), and in the opposite naris using a swab alone ("dry"). HCT recipients with a documented virologically-positive URI completed a symptom survey and collection procedure within 1 week of initial diagnosis; these subjects were followed weekly as feasible until negative. Swabs (Table Presented) were stored at ambient temperature, and PCR testing was performed for 12 RVs (positive value 5 threshold cycle [CT]\40). Results: Samples were collected during 106 URIs in 70 immunocompetent persons; 3 subjects were < 6 yo (parent performed). Counting all positive respiratory virus detections as true positives, sensitivity was 88/91 = 97% for wet swabs and 81/91 = 91% for dry (Table). Among 30 HCT recipients aged > 6 yo, 105 paired samples were collected during 30 URIs (median 3 samples/patient, range 1-9). Sensitivity was 83/95 = 87% for wet swabs and 81/95 = 85% for dry. In both populations, discordant results were associated with higher averageCT values (i.e., lower viral load), and discordance was highest in samples collected fromHCTrecipients. Dry swabs, in particular, appeared to perform better in subjects with rhinorrhea than without. A subset of 73 immunocompetent subjects rated the self collected swabs simple (96%) and comfortable (88%); no epistaxis occurred with any collection. Conclusion: Ourmethod of foam swab self-collection of nasal secretions is simple, comfortable, and safe amongHCT recipients.Discordance between wet and dry swabs increased with lower viral load. Overall, thewet swab appeared to increase sensitivity for respiratory viral detection in both immunocompetent subjects and HCT patients.
Campbell, A. P., Kuypers, J., Callais, C. L., Guthrie, K. A., Englund, J. A., & Boeckh, M. (2012). Self Collection of Nasal Swabs for Diagnosis of Respiratory Viruses in Immunocompetent Volunteers and Hematopoietic Stem Cell Transplant (HCT) Recipients. Biology of Blood and Marrow Transplantation, 18(2), S345–S346. https://doi.org/10.1016/j.bbmt.2011.12.373