Leukocytes are an important defense cell in the body and usually if you encounter inflammation, whether it is pneumonia, acute gastroenteritis, or even central nervous system infections, most of them will cause elevated leukocytes. However, there are a few cases where leukocytes can be normal, such as mycoplasma infections in lung infections, and viral pneumonia, where leukocytes can be normal or even decreased, and some severe infections where leukocytes are decreased, so whether leukocytes are normal or not, high or low is not a decisive factor in determining whether it is pneumonia. The actual pneumonia is a very important part of the pneumonia process. The combination of these indicators can be used to determine the cause. Sometimes a low white blood cell count is a sign of a serious lung infection, so remember not to judge the condition by a single white blood cell when asking questions or seeing a doctor.