Influenza is the short form of influenza, which needs to be detected through routine blood tests, virus isolation, influenza virus antigen test, and serologic tests. 1. Routine blood test: Routine blood test usually checks the blood picture, influenza virus infection, etc. The white blood cells are usually not high or low, and the lymphocytes are relatively increased. 2. Virus isolation: Usually, the influenza virus is isolated from nasopharyngeal secretions, and virus isolation is an important criterion for confirming the diagnosis of influenza. 3. Influenza virus antigen examination: it is necessary to take the epithelial cells of the patient’s respiratory tract to check the influenza antigen, if the antigen is positive, the diagnosis of influenza can be made. 4. Serologic examination: Double serum anti-influenza virus antibody titers with 4-fold or more elevation in the early stage of illness and the recovery period are helpful for retrospective diagnosis. In case of suspected influenza symptoms, one should go to the hospital immediately and be given appropriate relevant examinations under the guidance of the doctor.