Validation of oral-nasal specimen collection for influenza and respiratory syncytial virus detection.

Objective: Respiratory virus testing is routinely performed and ways to obtain specimens aside from a nasopharyngeal swab are needed for pandemic preparedness. The main objective is to validate a self-collected oral-nasal swab for the detection of Influenza and respiratory syncytial virus (RSV).

Design: Diagnostic test validation of a self-collected oral nasal swab as compared to a provider-collected nasopharyngeal swab.

Setting: Emergency Department at Michael Garron Hospital.

Participants: Consecutive individuals who presented to the Emergency Department with a suspected viral upper respiratory tract infection were included if they self-collected an oral-nasal swab. Individuals testing positive for Influenza or RSV along with randomly selected participants who tested negative were eligible for inclusion.

Interventions: All participants had the paired oral-nasal swab tested using a multiplex respiratory virus polymerase chain reaction for the three respiratory pathogens and compared to the nasopharyngeal swab.

Results: 48 individuals tested positive for Influenza, severe acute respiratory coronavirus virus 2 (SARS-CoV-2) or RSV along with 80 who tested negative. 110 were symptomatic with the median time from symptom onset to testing of 1 day (interquartile range 2-5 days). Using the clinical nasopharyngeal swab as the reference standard, the sensitivity was 0.75 (95% CI, 0.43-0.95) and specificity was 0.99 (95% CI, 0.93-1.00) for RSV, sensitivity is 0.67 (95% CI, 0.49-0.81) and specificity is 0.96 (95% CI, 0.89-0.99) for Influenza.

Conclusions: Multiplex testing with a self-collected oral-nasal swab for Influenza and RSV is not an acceptable substitute for a healthcare provider collected nasopharyngeal swab primarily due to suboptimal Influenza test characteristics.