The diagnosis of Influenza A (H3N2) is based on a combination of the patient’s signs and symptoms as well as the results of ancillary tests. When influenza A (H3N2) infects the human body, it will lead to typical flu-like symptoms, such as muscle pain, cough, sore throat, runny nose, and difficulty in breathing. Severe cases may also cause neurological damage leading to headache, coma or impaired consciousness, which can be used as a basis for diagnosis. In addition to the patient’s clinical signs, the diagnosis of influenza A (H3N2) requires the combination of ancillary diagnostic findings such as nucleic acid tests, imaging tests and routine blood tests. The diagnosis of influenza A (H3N2) can be confirmed when nucleic acid tests are positive and imaging tests show typical infected lesions in the respiratory system. Laboratory test results are important in confirming the diagnosis of influenza A (H3N2). After symptoms of suspected influenza A (H3N2) infection, you should go to the hospital in time for targeted treatment.