The main indicator of pneumonia is a white blood cell count of >10×10^9/L or <10×10^9/L. The main indicator of infection is white blood cells, which are divided into three main categories, including granulocytes, monocytes and lymphocytes. Granulocytes are mainly neutrophils, and an increase in neutrophils can reflect septic infections; the higher the neutrophils, the more pronounced the septic infection. An increase in neutrophils can also reflect tissue damage and some other conditions. The increase in lymphocytes may reflect infections, mainly viral, but also specific pathogens, such as tuberculosis, and some tumor-related indicators. The increase in monocytes is also indicative of recovery from some acute infections, as well as tuberculosis or some hematologic diseases, where monocytes may also be increased.