Elevated monocyte counts are usually the result of physiologic as well as pathologic causes (e.g., infectious diseases, blood disorders, etc.), but they do not cause disease. Increased monocyte percentage means an increase in the number of monocytes in the body. The clinical reference value for monocyte percentage is 3%-8%, and it is normal for infants and children to have an increased monocyte percentage. Monocytes are the largest blood cells in the human blood circulation, with a diameter of 14-20 um, mostly round or irregular, and are an important part of the body’s defense system. Some infectious diseases or hematologic disorders may cause an increase in monocytes. When a patient has an increased monocyte percentage, he/she needs to consult a doctor in time and take symptomatic treatment under the doctor’s guidance.