Monocyte percentage of 20 is on the high side and requires attention, as well as care not to be overly anxious, and may be due to non-disease causes. The normal range for monocyte percentage is 3% to 8%, and a monocyte percentage of 20% is considered high. Common causes include inaccurate monocyte counts due to antibiotics, the presence of certain infections such as acute infections in recovery, active tuberculosis, infective endocarditis, etc., and the presence of certain blood disorders such as mononuclear cell leukemia and chronic granulocytic leukemia. When the percentage of monocytes is elevated, other data should also be comprehensively examined. If blood diseases are suspected, it is recommended that further examinations such as CT, ultrasound, bone marrow cytology test, etc. be conducted under the guidance of a doctor to clarify the cause of the disease and provide targeted treatment in a timely manner, so as to avoid delaying the condition and the treatment.