An HRP‐labeled lateral flow immunoassay for rapid simultaneous detection and differentiation of influenza A and B viruses

Rapid and sensitive diagnosis of influenza is urgently needed to address the limitations of low sensitivity associated with current rapid tests available for clinics and on‐site monitoring. A novel horseradish peroxidase (HRP)‐labeled lateral flow immunoassay strip (HRP‐LFIA) for rapid simultaneous detection and differentiation of influenza A (INF A) and influenza B (INF B) viruses were developed. This immunoassay was based on the signal amplification by the HRP‐catalyzed oxidation of 3, 3′, 5, 5′‐tetramethylbenzidine forming a colored insoluble product, which was proportional to the analyte concentration. Compared with conventional gold‐colloidal based strips, an analytical sensitivity enhancement of more than one order of magnitude for thirteen INF virus isolates was observed. A total of 1487 swabs obtained from persons with influenza‐like illnesses were tested for the presence of INF A and B viruses using real‐time reverse transcription polymerase chain reaction (rRT‐PCR) as the reference criterion. The overall sensitivities of HRP‐LFIA were 77.5% (100/129) and 71.2% (116/163) for INF A and INF B, respectively. The overall specificities were 99.8% (1144/1146) and 99.8% (918/920), respectively. The nasopharyngeal sampling method yielded higher sensitivity rates of 90.2% (55/61) and 82.6% (71/86). In conclusion, this user‐friendly assay could be a promising rapid detection method for rapid screening of INF A and INF B viruses. A novel immunoassay based on the signal amplification by the HRP‐catalyzed oxidation of 3, 3’, 5, 5’‐tetramethylbenzidine was established. Compared with conventional gold based strips, an analytical sensitivity enhancement of more than one order of magnitude was observed.