The difference between viral and bacterial infections receiving routine blood tests can be made by the white blood cells as well as the neutrophils. 1. Viral infections: generally do not cause elevation of neutrophils and leukocytes, and may even show a drop in symptoms. However, it can cause an increase in lymphocytes and even the production of heterogeneous lymphocytes. In addition, antibody tests and nucleic acid tests are required to determine the type of virus infection. 2. Bacterial infections: generally induce a marked increase in neutrophils as well as white blood cells. For bacterial infections, blood cultures and calcitoninogen tests are also required to confirm the type of bacterial infection with the help of blood cultures. Whether it is bacterial infection or viral infection, there is a certain degree of harm, the role of blood test in the diagnostic process is limited, it is recommended that the patient consult a doctor in a timely manner, under the guidance of specialists for further examination, diagnosis is clear and active treatment.