Influenza B can be clinically diagnosed through symptoms, but also based on some relevant tests to confirm the diagnosis, the specific tests are as follows: 1, peripheral blood examination: the total number of white blood cells generally does not increase or decrease, mainly lymphocytes increase, severe patients can increase the white blood cells. If bacterial infection is combined, the white blood cell and neutrophil count will increase; 2. Blood biochemical examination: some cases may show hypokalemia, and a few patients may show elevated creatine kinase, transaminase, lactate dehydrogenase and creatinine; 3. Pathogenic correlation examination: mainly includes virus isolation, virus antigen, nucleic acid and antibody detection. Virus isolation is mainly carried out in the laboratory and is of great significance for clinical diagnosis. In addition, the virus antigen and nucleic acid examination is more significant for the early diagnosis of influenza B virus; antibody detection is generally used clinically as a retrospective survey and analysis of cases, which is not particularly significant for early diagnosis; 4, imaging: early imaging of patients with influenza B has no obvious changes, some patients can appear bronchial texture thickening and other signs of bronchial infection, severe patients Pulmonary infiltrative lesions can appear, and in severe cases, pleural effusion can appear, or even fusion into pieces.