The routine blood report includes cell count, cell classification, and now the five common classifications of white blood cells, namely neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Viral infections mainly look at the lymphocyte ratio and the absolute value. Routine viral infections can cause elevated lymphocytes, often greater than 60%. Both an elevated lymphocyte ratio and an elevated absolute value usually indicate a possible viral infection. Viral infections are also judged in the context of the patient’s own condition and clinical symptoms, and relevant virological testing is performed when necessary to clarify exactly what virus is causing the infection in question.