Detection of influenza A and B with the Alere™ i Influenza A & B: a novel isothermal nucleic acid amplification assay

BackgroundRapid influenza diagnostic tests (RIDTs) have an important role in clinical decision-making; however, the performances of currently available assays vary widely. ObjectivesWe evaluated the performance of the Alere i Influenza A&B (Alere iNAT), a rapid isothermal nucleic acid amplification assay that has recently received FDA clearance, for the detection of influenza A and B viruses during the Australian influenza season of 2013. Results were compared to two other RIDTs tested in parallel; Quidel Sofia((R)) Influenza A+B fluorescent immunoassay (FIA) and Alere BinaxNOW((R)) Influenza A & B immunochromatographic (ICT) assay. MethodsA total of 202 paired nasopharyngeal swabs collected from patients 16years old with an influenza-like illness (ILI) were eluted in 2ml of universal transport medium (UTM) that was used to perform all three RIDTs in parallel. Reverse-transcription polymerase chain reaction (RT-PCR) was used as the reference standard. ResultsCompared to RT-PCR, Alere iNAT detected 778% influenza A positive samples versus 714% and 444% for the Quidel Sofia((R)) Influenza A+B FIA and BinaxNOW((R)) Influenza A & B ICT assay, respectively. For influenza B, Alere iNAT detected 75% of those positive by RT-PCR, versus 333% and 250% for Sofia((R)) and BinaxNOW((R)), respectively. The specificity of Alere iNAT was 100% for influenza A and 99% for influenza B. ConclusionsAlere i Influenza A&B is a promising new rapid influenza diagnostic assay with potential point-of-care applications.