The influenza virus is classified into four types A, B, C, and D, but type A and B are responsible for major illnesses in people with influenza A being the only virus responsible for flu pandemics due to the presence of two surface proteins called hemagglutinin (H) and neuraminidase (N) on the virus. The two subtypes of influenza A virus, H1N1 and H3N2, have been known to cause many flu pandemics. Both subtypes change genetically and antigenically to produce variants (clades and subclades, also know as groups and subgroups). H3N2 tends to change rapidly, both genetically and antigenically whereas that of H1N1 generally tends to have smaller changes. Influenza A (H3N2) viruses have evolved to form many separate, genetically different clades that continue to co-circulate. Influenza A(H3N2) viruses have caused significant deaths as per WHO report. The review describes methods for detection of influenza A(H3N2) viruses by conventional serological methods as well as the advanced methods of molecular biology and biosensors. All these methods are based on different parameters and have different targets but the goal is to improve specificity and increase sensitivity. Amongst the molecular methods, real-time polymerase chain reaction (RT-PCR) is considered a gold standard test due to its many advantages whereas a number of other molecular methods are time-consuming, complex to perform or lack specificity. The review also considers bio-sensing methods for simple, rapid, highly sensitive, and specific detection of H3N2. The classification and principle of various H3N2 biosensors are also discussed.

流感病毒分为甲型、乙型、丙型和丁型四种，但甲型和乙型流感病毒是导致人类重大疾病的原因，甲型流感病毒是唯一导致流感大流行的病毒，因为存在两种称为血凝素的表面蛋白(H) 和病毒上的神经氨酸酶 (N)。已知甲型流感病毒的两种亚型 H1N1 和 H3N2 会引起许多流感大流行。两种亚型都会发生遗传和抗原性变化，产生变体（进化枝和亚进化枝，也称为群体和亚群）。H3N2 的基因和抗原性变化往往很快，而 H1N1 的变化通常较小。甲型流感 (H3N2) 病毒已进化形成许多独立的、基因不同的分支，并继续共同传播。根据世界卫生组织的报告，甲型 H3N2 流感病毒已造成大量死亡。该综述描述了通过传统血清学方法以及分子生物学和生物传感器的先进方法检测甲型H3N2流感病毒的方法。所有这些方法都基于不同的参数并具有不同的目标，但目标是提高特异性和灵敏度。在分子方法中，实时聚合酶链反应（RT-PCR）因其许多优点而被认为是金标准测试，而许多其他分子方法耗时、执行复杂或缺乏特异性。该综述还考虑了简单、快速、高灵敏度和特异性检测 H3N2 的生物传感方法。还讨论了各种H3N2生物传感器的分类和原理。