The normal range of lymphocyte is 20%～40%, 49% is a bit high, simple lymphocyte increase is not very serious, if there are other uncomfortable symptoms, need to combine with other tests and conditions to determine the severity of the disease. Common causes of increased lymphocyte percentage include relative increase, infectious disease, blood disease, etc. 1. Relative increase: Lymphocyte values are relatively higher due to the decrease of other cells, but the absolute value of lymphocytes does not increase, such as aplastic anemia, tumors and other diseases. 2. Infectious diseases: viral infections may cause elevated lymphocyte values, such as viral hepatitis, measles, chicken pox and other diseases. 3. Blood disorders: Blood disorders such as aplastic anemia and lymphoblastic leukemia may cause elevated lymphocyte counts. Higher lymphocyte counts may also be caused by other reasons, so you should bring the test results to the hospital for a follow-up consultation, and the doctor will make a comprehensive judgment of the cause of the disease according to the test results and provide targeted treatment.