Infection and Drug Resistance (May 2024)
Clinical Performance of Self-Collected Purified Water Gargle for Detection of Influenza a Virus Infection by Real-Time RT-PCR
Abstract
Guiling Li,1– 3,* Tianyang Tan,3– 5,* Luting Chen,3– 5 Jiaqi Bao,3– 5 Dongsheng Han,3– 5 Fei Yu3– 5 1Department of Clinical Laboratory, Sir Run Run Shaw Hospital of Medicine Zhejiang University, Hangzhou, 310003, People’s Republic of China; 2Key Laboratory of Precision Medicine in Diagnosis and Monitoring Research of Zhejiang Province, Hang-zhou, 310003, People’s Republic of China; 3Institute of Laboratory Medicine, Zhejiang University, Hangzhou, 310003, People’s Republic of China; 4Department of Laboratory Medicine, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, People’s Republic of China; 5Zhejiang Key Laboratory of Clinical in vitro Diagnostic Techniques, Hangzhou, 310003, People’s Republic of China*These authors contributed equally to this workCorrespondence: Dongsheng Han; Fei Yu, Department of Laboratory Medicine, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, People’s Republic of China, Email [email protected]; [email protected]: Self-collected specimens are increasingly being used as alternatives to swab-based methods for the detection of respiratory viruses. While saliva is well accepted, gargle specimens are a potential alternative with characteristics that are more favorable for laboratory handling. This study assessed the performance of gargle specimens in the detection of influenza A viruses (IAVs).Patients and Methods: We performed a prospective head-to-head comparison between combined nasopharyngeal and oropharyngeal swabs (NPS&OPS) and purified water gargle (PWG) among adult outpatients with febrile respiratory symptoms to detect IAVs using real-time RT-PCR during two influenza seasons.Results: During study periods 1 (July 13 to 26, 2022, H3N2 predominated) and 2 (February 25 to March 10, 2023, H1N1 pdm09 predominated), a total of 459 patients were recruited. The overall agreement between the NPS&OPS and PWG was 85.0% (390/459, κ = 0.697), with 88.0% in period 1 and 82.6% in period 2. The detection rate of IAVs in PWG (51.6%, 237/459) was lower than that in NPS&OPS (62.3%, 286/459) (p < 0.0001). The overall sensitivity and specificity were 96.6% (93.7– 98.3%) and 100% (97.1– 100%) in NPS&OPS and were 80.1% (75.0– 84.4%) and 100% (97.1– 100%) in PWG, respectively. Among the 227 pairs of concordant positive specimens, cycle threshold (Ct) values were significantly lower in NPS&OPS than in PWG (median Ct values: 24.2, 28.2, p < 0.0001).Conclusion: Although self-collected PWG specimens offer acceptable performance for IAVs molecular testing, NPS&OPS remain a reliable option. Given the convenience of collection, nonviscous gargles are recommended for viral detection during emergencies or under specific conditions.Keywords: gargle, nasopharyngeal swab, oropharyngeal swab, detection, influenza A virus, rRT-PCR
