Neutrophils are derived from hematopoietic stem cells of the bone marrow, which differentiate and develop in the bone marrow and then enter the blood or tissues. The ratio of the number of distribution in the bone marrow, blood and connective tissue is 28:1:25, and the number of neutrophils in the blood of adults is about 55%-70% of the total number of white blood cells look. A higher value of the percentage of neutrophils indicates that the disease is still developing and is likely to worsen further. Mainly for bacteria, neutrophils tend to increase when the body is infected with bacteria. If the neutrophil percentage decreases, the lymphocyte percentage has to increase accordingly, indicating a possible viral infection.