Normally, the normal absolute value of lymphocytes in the human body is usually between (0.8-4) × 10^9/L by routine blood tests, and the normal value of the percentage of lymphocytes in the human body is usually between 20% and 40%. Lymphocytes are a type of human leukocytes, the smallest white blood cells, produced by the lymphoid organs and mainly found in the lymphatic fluid, which is an important cell for the immune function of the body. Lymphocytes have the function of producing and transporting antibodies and defending against viral infections.