Comparison of Four Rapid Diagnostic Kits of Immunochromatography for Detection of Influenza A and Influenza B Viruses

Objective: The objective was to compare the performance of four commercial rapid influenza virus antigen detection test kits, namely QuickNavi-Flu (Denka Seiken, Tokyo, Japan), Alere BinaxNOW Influenza A&B assay (Alere Scarborough, Scarborough Inc., Scarborough, ME, USA), KaiBiLi Genesis Influenza A&B Antigen Test (Genesis, Hangzhou, China) and Actim Influenza A&B (Medix Biochemica, Kauniainen, Finland). Methods: CAP proficiency testing specimens and ultrasonic lysates of normal human lung fibroblast cell (MRC-5 at 2.9 × 106/ mL) were taken as specimens. The supernatants of influenza A and influenza B were used as stock solutions, and, using saline, were diluted to 1:10 and then serially diluted to 1:100, 1:200, 1:400, 1:800, 1:1600, and 1:3200. The dilutions were tested respectively to evaluate the sensitivity of these kits. Respiratory syncytial virus, adenovirus, Para influenza virus type-2 and MRC-5 cell were taken as samples to evaluate the specificity of these kits. Influenza A (H1N1) at a dilution of 1:200, influenza A (H3N2) at a dilution of 1:100 and influenza B at a dilution at 1:100 were used to detect the reproducibility. Each sample was tested nine times in total. Results: In this experiment, the four commercial kits showed the same detection limit for influenza A (H3N2) where all the kits could not give positive result for dilutions lower than 1:100. On the contrary, different detection limits were obtained for influenza A (H1N1) and influenza B. For influenza A (H1N1), positive results could be obtained using a dilution at 1:800 by Quick Navi Flu yet positive results could only be obtained at the dilution of 1:200 using the other three kits. All the results showed that timely detection gave better sensitivity than delayed detection except detection for Influenza A (H1N1) by the Alere BinaxNOW kit where dried specimens gave slightly higher sensitivity. The Actim kit showed positive result for Influenza B when detecting the ultrasonic lysates of MRC-5 cell, illustrating that false positive result may be obtained when detecting specimens which contain components related to MRC-5 cell using Actim kit. There was no non-specific cross-reactivity for the other three kits. In general, all these kits provided good reproducibility except that results of of Influenza A (H1N1) detection using the Alere BinaxNOW kit were inconsistent. Conclusions: Various performances were found for the detection of influenza A and B viruses using four rapid immunochromatography diagnostic kits most commonly used in China.