The diagnosis of encephalitis in children cannot be confirmed by blood tests alone. Encephalitis is an infection of the central nervous system that can present with headache, vomiting, convulsions, coma, and can present with localization signs, meningeal irritation signs, cervical resistance, Creutzfeldt-Jakob sign, Bruch’s sign, and a negative Pap sign. To confirm the diagnosis of encephalitis, the best standard is lumbar puncture. For the cerebrospinal fluid obtained by lumbar puncture, routine cerebrospinal fluid, cerebrospinal fluid biochemistry, and cerebrospinal fluid pathogenesis are performed to determine the type of encephalitis. Lumbar puncture can also be used to determine the pressure of the cerebrospinal fluid and to determine if there is cranial hypertension. Antibody tests can be performed by drawing blood once in the acute phase to determine pathogenic antibodies in the acute phase and once in the recovery phase to determine pathogenic antibodies in the recovery phase. If it is higher than 4 times, it can be determined which antigen is responsible for the viral encephalitis.