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.


OBJECTIVE
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.
Centre for Infectious Diseases and Microbiology Laboratory Services, Institute for Clinical Pathology and Medical Research, Westmead Hospital, Westmead, NSW, Australia; Westmead Clinical School, University of Sydney, Westmead Hospital, Westmead, NSW, Australia.
Briony
B
Hazelton
Timothy
T
Gray
Jennifer
J
Ho
V Mala
VM
Ratnamohan
Dominic E
DE
Dwyer
Jen
J
Kok
D000328:Adult; D001315:Australia; D002846:Chromatography, Affinity; D005260:Female; D006801:Humans; D009980:Influenza A virus / Q000235:genetics / Q000302:isolation & purification*; D009981:Influenza B virus / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques; D021141:Nucleic Acid Amplification Techniques; D019095:Point-of-Care Systems; D012015:Reference Standards; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012621:Seasons; D012680:Sensitivity and Specificity; D055815:Young Adult
Influenza; isothermal nucleic acid amplification; rapid diagnostic test(s); sensitivity; specificity