SAN DIEGO — Nasopharyngeal flocked swabs are significantly more effective than nasopharyngeal aspirates for recovery of respiratory viruses, according to a nostril-to-nostril comparative study.
The cost of the flocked swab method was 58% less in terms of equipment and procedural time than for nasopharyngeal aspiration in this 106-patient study, Dr. Gaurav Sangwan reported at the annual meeting of the American College of Chest Physicians.
Moreover, the nasopharyngeal flocked swabs were significantly more environmentally friendly, with a carbon footprint less than 5% of that involved in obtaining nasopharyngeal aspirates. Health care personnel participating in the study indicated they found the flocked swabs easier to use and preferable to obtaining nasopharyngeal aspirates. Nasopharyngeal flocked swab sample collection is also far more amenable to outpatient settings, added Dr. Sangwan of Southern Illinois University, Springfield.
Each of the 106 study participants with suspected viral respiratory infection underwent flocked swabbing of one nostril and nasopharyngeal aspiration in the other. Swabbing yielded 67 positive results, significantly more than the 60 positives with nasopharyngeal aspiration.
Respiratory syncytial virus was detected by immunoassay in 25 specimens obtained by flocked swabbing and in 21 nasopharyngeal aspirates. Immunoassays for influenza A/B were positive in 10 flocked swab specimens and 4 nasal aspirates. Direct fluorescent antibody testing for respiratory viruses was positive in eight flocked swab samples and three nasopharyngeal aspirates. Culture was positive for 24 flocked swab samples and 28 nasopharyngeal aspirates.
The average estimated yield of epithelial cells rated by laboratory personnel on a 1-4 scale was a score of 3.6 per flocked swab and 3.0 per nasal aspirate.
Traditional fiber or foam swabs have been shown to be inferior to nasopharyngeal aspirates in terms of the amount of the sample obtained for respiratory virus diagnostic testing. Nasopharyngeal flocked swabs, a proprietary technology recently developed by Copan Diagnostics, overcome the problems of poor sample uptake and release inherent to traditional swabs. The flocked swabs utilize a brushlike action to dislodge epithelial cells and capillary hydraulics to draw liquid material between the swab fibers.
Disclosures: Dr. Sangwan's study was funded in part by research grants from Copan Diagnostics and Diagnostic Hybrids Inc.