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

BACKGROUND Rapid influenza diagnostic tests (RIDTs) have an important role in clinical decision-making; however, the performances of currently available assays vary widely. OBJECTIVES We 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(®) Influenza A+B fluorescent immunoassay (FIA) and Alere(™) BinaxNOW(®) Influenza A & B immunochromatographic (ICT) assay. METHODS A total of 202 paired nasopharyngeal swabs collected from patients ≥ 16 years old with an influenza-like illness (ILI) were eluted in 2 ml 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. RESULTS Compared to RT-PCR, Alere(™) iNAT detected 77.8% influenza A positive samples versus 71.4% and 44.4% for the Quidel Sofia(®) Influenza A+B FIA and BinaxNOW(®) Influenza A & B ICT assay, respectively. For influenza B, Alere(™) iNAT detected 75% of those positive by RT-PCR, versus 33.3% and 25.0% for Sofia(®) and BinaxNOW(®), respectively. The specificity of Alere(™) iNAT was 100% for influenza A and 99% for influenza B. CONCLUSIONS Alere(™) i Influenza A&B is a promising new rapid influenza diagnostic assay with potential point-of-care applications.