An elevated lymphocyte percentage for many years is not normal. Lymphocyte percentage refers to the lymphocyte count in the peripheral blood as a percentage of the total number of white blood cells. An elevated lymphocyte percentage may be caused by a pathologic condition, such as chronic lymphocytic leukemia and acute lymphocytic leukemia, or it may be a physiologic change. Elevated lymphocyte percentages due to diseases such as chronic lymphocytic leukemia and acute lymphoblastic leukemia are persistently elevated and are accompanied by elevated absolute lymphocyte values. In chronic lymphocytic leukemia, the increase is gradual and the disease progresses slowly, but in acute lymphoblastic leukemia, the disease progresses rapidly, and if left untreated, the patient’s survival may be only a few months. Physiologic elevations in lymphocyte counts are often not accompanied by elevated absolute lymphocyte counts and are temporary, returning to normal on their own. Therefore, an elevated lymphocyte percentage for many years is usually a sign of abnormality and is most likely due to chronic lymphocytic leukemia. It is recommended that the patient should consult the hematology department in time, complete the examination such as bone marrow aspiration and biopsy in order to make a clear diagnosis, and formulate an individualized treatment plan according to the patient’s specific situation, and actively treat the disease.