Effectiveness of patient-collected swabs for influenza testing

Abstract

Objective: To compare the effectiveness of self-collected and health care worker (HCW)-collected nasal swabs for detection of influenza viruses and determine the patients' preference for type of collection.

Patients and methods: We enrolled adult patients presenting with influenzalike illness to the Emergency Department at Mayo Clinic, Rochester, Minnesota, from January 28, 2011, through April 30, 2011. Patients self-collected a midturbinate nasal flocked swab from their right nostril following written instructions. A second swab was then collected by an HCW from the left nostril. Swabs were tested for influenza A and B viruses by real-time reverse transcription-polymerase chain reaction, and percent concordance between collection methods was determined.

Results: Of the 72 paired specimens analyzed, 25 were positive for influenza A or B RNA by at least one of the collection methods (34.7% positivity rate). When the 14 patients who had prior health care training were excluded, the qualitative agreement between collection methods was 94.8% (55 of 58). Two of the 58 specimens (3.4%) from patients without health care training were positive only by HCW collection, and 1 of 58 (1.7%) was positive only by patient self-collection. A total of 53.4% of patients (31 of 58) preferred the self-collection method over the HCW collection, and 25.9% (15 of 58) had no preference.

Conclusion: Self-collected midturbinate nasal swabs provide a reliable alternative to HCW collection for influenza A and B virus real-time reverse transcription-polymerase chain reaction.

FIGURE 1

Patient instructions for midturbinate nasal swab collection.

FIGURE 2

Proposed model for patient-collected midturbinate nasal swabs for influenza polymerase chain reaction assay. An influenzalike illness (A) prompts the patient to call the Nurse Triage Center (B), where a nurse assesses the patient's condition via a standardized phone questionnaire. If eligible, the patient is offered the opportunity to self-collect a nasal swab in lieu of an office visit. A prescription for oseltamivir is generated and placed with a swab kit. The patient or caregiver obtains the swab kit from an easy-access point (C) and uses the midturbinate nasal flocked swab to obtain a sample following written instructions (D). The swab is then delivered to the clinical microbiology laboratory for polymerase chain reaction assay (E), along with a precompleted prescription. If the swab is positive for influenza, the prescription is sent to the patient's pharmacy. The patient receives the test result by an automated phone system (F), along with information to pick up the prescription if the test is positive (G).