Adolescents with nosebleeds should undergo electronic nasopharyngoscopy, blood test, coagulation function and other tests. 1. Electronic nasopharyngoscopy: Through the examination of electronic nasopharyngoscopy to identify the bleeding point, to clarify whether there is the presence of nasal septum deviation, nasal polyps, rhinitis and other conditions that may cause nosebleeds. 2. blood routine: on one hand, we can check the hemoglobin, red blood cell count, hematocrit and other indicators to determine whether the patient has anemia caused by excessive bleeding. On the other hand, platelet count and white blood cell count can be checked to rule out the existence of blood diseases, such as leukemia and aplastic anemia. 3. Coagulation function: by checking the prothrombin time, fibrinogen and other indicators to rule out the existence of coagulation dysfunction and other conditions. When adolescents have nosebleeds, it is recommended to consult a doctor as soon as possible for a clear diagnosis and standardized treatment as prescribed by the doctor.