Improving the Quality of Nasal Specimen Collection for Influenza A and B Screening

Contribution to Emergency Nursing Practice
- Compared with nasopharyngeal aspirate or nasopharyngeal swab techniques, nasal swab is more comfortable for patients and may be easier for the emergency nurse to use.
- Instillation of sterile saline into the nares, or “Wet Swab,” is used in an attempt to improve specimen collection and preservation of viral material.
- The Wet Swab method may be clinically superior for detecting influenza in adults presenting later in the course of illness. Inserting the swab in gel medium may also increase moisture.
- Emergency nurses should be engaged in decision-making for supplies and changes in supplies, and manufacturers' instructions for supplies they use in clinical practice.
- Definitive diagnosis of Influenza, even beyond the 48-hour antiviral treatment window, may inform patient teaching and interventions to prevent spread to close contacts.ProblemRapid diagnosis of seasonal influenza leads to optimized clinical care and reduces the spread of infection. The collection of adequate cellular material can be facilitated by the presence of moisture in the nares. The specific aim of this project was to determine if the installation of sterile saline into the nares prior to specimen collection would improve the quality of the specimen.MethodsThis quasi-experimental single group design tested an initial “dry swab” specimen against a second swab after instillation of sterile saline solution using a nasal atomizer, a “wet swab.”ResultsA total of 80 paired specimens were collected and analyzed between December 7, 2015, and April 21, 2016, with an 11.25% infection rate in those tested. Of 9 positive tests, 6 subjects tested positive for influenza A or B for both the dry swab and the wet swab. Three subjects tested positive for influenza A or B for only the wet swab, and these subjects had experienced their symptoms longer than did subjects who tested positive for both methods (mean symptom onset of 72 hours vs 66 hours). We found an important inconsistency between manufacturers' recommendations and typical hospital practice.Implications for PracticeThe results appear somewhat equivocal. Because viral shedding declines after the first 48 to 72 hours in adults, the wet swab method may be clinically superior for detecting influenza in adults presenting later in the course of their illness. Hospital policy was revised for consistency in using the gel medium before sampling in accordance with manufacturer recommendations.