According to the Hormone-Refractory Prostate Cancer Association, "LY" on a blood test stands for lymphocytes. The number in the results represents the percentage of lymphocytes in the white blood count. Lymphocytes should count for 15 to 46.8 percent of white blood cells.
Lymphocytes are comprised of T lymphocytes and B lymphocytes. The HRPCa Association explains that T lymphocytes help detect and eliminate cancer cells and are vital in protecting the body against viral infections. B lymphocytes are white blood cells that transform into cells that produce antibodies. Lymphocytes are produced in the lymph nodes and spleen. In young children and adults, the thymus gland creates mature T lymphocytes. Low white blood cell count indicates a suppressed immune system.