Gargle sample is an effective option in a novel fully automated molecular point-of-care test for influenza: a multicenter study

Abstract

We conducted a multicenter study to evaluate a novel transcription-reverse transcription concerted reaction (TRC) that can detect influenza A and B within 15 minutes. We evaluated this rapid TRC using nasopharyngeal swab and gargle samples obtained from patients who visited or were hospitalized at eight clinics and hospitals with influenza-like illnesses between December 2019 and March 2020. After obtaining informed consent, we collected nasopharyngeal swabs from all patients using two swabs and gargle samples from patients whom the physician judged fit to perform gargling. We evaluated 133 nasopharyngeal swabs and 213 gargle samples from 244 patients. In nasal swabs, influenza A or B was detected in 96 and 98 patients using reverse transcription-polymerase chain reaction (RT-PCR) and TRC, respectively. Influenza A and B were detected using sequence analysis in four patients with different RT-PCR and TRC results. Based on the combined RT-PCR and sequencing results, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of TRC for influenza detection were 0.990, 1.000, 1.000, and 0.993, respectively. In the gargle samples, influenza A was detected in 100 and 99 patients using RT-PCR and TRC, respectively. Influenza A was detected using sequencing in five patients with different RT-PCR and TRC results. The sensitivity, specificity, PPV, and NPV of the TRC for detecting influenza were 0.970, 0.982, 0.980, and 0.974, respectively. The novel rapid TRC was comparable to RT-PCR for the detection of influenza in nasopharyngeal swabs and gargle samples.