Advances in influenza A and B virus detection: molecular diagnostics, biosensors, and point-of-care applications

Influenza A and B viruses remain major causes of seasonal epidemics and continue to pose substantial challenges for rapid clinical diagnosis and public-health surveillance. Conventional methods, including viral culture, immunological assays, and reverse-transcription real-time quantitative PCR (RT-qPCR), provide important diagnostic benchmarks but are constrained by long turnaround times, dependence on specialized equipment, or reduced sensitivity in low-viral-load specimens. This review summarizes recent advances in influenza virus detection, with emphasis on molecular diagnostics, biosensors, point-of-care testing, and high-throughput sequencing. Digital PCR offers precise absolute quantification, whereas isothermal amplification technologies such as reverse transcription loop-mediated isothermal amplification (RT-LAMP) and reverse transcription recombinase polymerase amplification (RT-RPA) reduce reliance on thermal cycling and support portable testing. CRISPR-Cas systems further improve sequence specificity and are increasingly being integrated with isothermal amplification, lateral-flow readouts, and microfluidic platforms. Biosensor strategies based on optical, electrochemical, multimodal, and smartphone-assisted readouts provide promising routes for rapid, multiplexed, and point-of-care detection, although standardization and large-scale clinical validation remain key barriers. High-throughput sequencing complements rapid testing by enabling viral typing, variant monitoring, and emerging-pathogen monitoring. Overall, future influenza diagnostics are expected to move toward integrated, low-cost, "sample-in, answer-out" systems that combine sensitivity, speed, portability, and surveillance connectivity.