The diagnosis of pneumonia mainly relies on its clinical manifestations. For example, patients may have cough, expectoration, accompanied by shortness of breath and difficulty breathing. Most patients may also have a fever. Clinically, moist rales may sometimes be heard during lung auscultation, sometimes accompanied by weakened breath sounds and bronchovesicular breath sounds. At the same time, combined with chest X - rays, it can show the imaging manifestations of bronchopneumonia. If the same pathogenic bacteria are isolated from sputum culture twice in a row, pneumonia can be diagnosed. Whether the white blood cell count is normal is not a key indicator for pneumonia. Usually, when pneumonia occurs, the total white blood cell count may increase, but it may also be normal. In the case of bacterial infection, the total white blood cell count often increases, and there is often a phenomenon of left - shift of the nucleus, accompanied by an increase in C - reactive protein. In the case of viral infection, the white blood cell count may be normal. Therefore, a normal white blood cell count does not rule out pneumonia.