Bacterial and viral infections involve a wide variety of pathogens and differ in the presentation of routine blood tests. The vast majority of bacterial infections show an increase in total white blood cell count, neutrophil count, and neutrophil percentage, but specific bacteria have some specific manifestations. In viral infections, white blood cells are usually decreased, neutrophils are decreased, and lymphocytes are increased, but there are some specific infections that can present with special conditions. The following describes the blood routine of some common infections: I. Bacterial infections 1. Mycobacterium tuberculosis: usually shows a normal total white blood cell count and a normal neutrophil count, but there are some special severe cornual tuberculosis that can show a decrease in total white blood cell count and a decrease in neutrophil count; 2. Mycobacterium brucei: often shows a normal or decreasing total white blood cell count and an increase in lymphocyte count or proportional rise; 3, Listeria monocytogenes: often shows an increase in total leukocytes, but mainly elevated monocytes; 4, Bacillus pertussis: shows an increase in total leukocytes, with a significant increase in the proportion of lymphocytes; 5, S. typhi, S. paratyphi: often shows a decrease in total leukocytes and a decrease in granulocyte count. Second, viral infections 1, influenza virus: patients often show a decrease in total leukocyte count and an increase in the proportion of lymphocytes; 2, EBV, cytomegalovirus, hantavirus: manifested as an increase in total leukocyte count, dominated by an increase in the proportion of lymphocytes, and can see heterotypic lymphocytes; 3, B encephalitis virus: often manifested as an increase in total leukocyte count and an increase in the count and percentage of neutrophils; 4. B19 infection: the prominent manifestation is a decrease in hematocrit, which means that significant anemia can be seen; 5. measles virus and rubella virus: often show a decrease in total leukocyte count and an increase in lymphocyte ratio; 6. dengue virus: often show a decrease in total leukocyte count and a decrease in neutrophils; 7. novel Bunyavirus: a decrease in total leukocyte count, granulocytes, and platelets. The specific blood routine performance depends on the type of disease and the progress of the patient, and the patient can ask the doctor to check further after getting the blood routine results.