The normal value of lymphocyte percentage is between 20% and 40%. If a patient’s test results show a decrease in lymphocyte percentage, this may be due to a disease of the autoimmune system, commonly known as a cellular immunodeficiency disease. It can also be caused by radiation sickness, which is mainly due to prolonged exposure to radiation, which can also lead to a decrease in lymphocyte percentage. It can also be caused by an acute infectious disease, which can also lead to a decrease in lymphocyte percentage. If the patient only has a reduced lymphocyte percentage, the result is generally not particularly significant, so it is recommended that the patient must decide on further tests based on the specific situation, and after a clear diagnosis, it is recommended that the patient must actively treat the symptoms to avoid serious complications.