Evaluation of a rapid diagnostic test, NanoSign® Influenza A/B Antigen, for detection of the 2009 pandemic influenza A/H1N1 viruses

Background: This study evaluated the clinical accuracy and analytical sensitivity of the NanoSign (R) Influenza A/B antigen kit in detecting 2009 pandemic influenza A/H1N1 viruses. The kit is one of the most popular rapid diagnostic tests for detecting influenza in Republic of Korea. Results: The NanoSign (R) Influenza A/B kit resulted in 79.4% sensitivity and 97.2% specificity compared to RT-PCR in the detection of the viruses from 1,023 specimens. In addition, the kit was able to detect two strains of novel influenza viruses, Influenza A/California/12/2009(H1N1) and clinically isolated wild-type novel influenza A/H1N1, both of which are spreading epidemically throughout the world. In addition, the correlation between NanoSign (R) Influenza A/B test and conventional RT-PCR was approximately 94%, indicating a high concordance rate. Analytical sensitivity of the kit was approximately 73 +/- 3.65 ng/mL of the purified viral proteins and 1.13 +/- 0.11 hemagglutination units for the cultured virus. Conclusions: As the NanoSign (R) Influenza A/B kit showed relatively high sensitivity and specificity and the good correlation with RT-PCR, it will be very useful in the early control of influenza infection and in helping physicians in making early treatment decisions.