Blood tests for patients with pneumonia often show an increase in the white blood cell count and neutrophil ratio, but the white blood cell count may not increase in elderly, weak, immunocompromised patients, or patients who are alcoholics, or who have taken a large amount of antipyretic medication by mouth. In addition to routine blood tests, patients with pneumonia should be tested for C-reactive protein and calcitoninogen, which can reflect the active stage of inflammation and its severity. According to the patient’s typical symptoms and signs, and in combination with X-ray examination of the chest as well as sputum culture and smear etiology, the diagnosis and treatment of pneumonia can be clarified, and the monitoring of routine blood tests alone cannot reflect the condition of pneumonia and the treatment of the disease.