B AND T CELL COUNTS - A test that measures the respective quantities of B lymphocytes and T lymphocytes. This test is often performed in the analysis of an immune deficiency disorder. Normal values include: 68 to 75% of total lymphocytes are T lymphocytes and 10 to 20% are B lymphocytes. Increased T cell counts can indicate infectious mononucleosis, acute lymphocytic leukemia, or multiple myeloma. Increased B lymphocytes can indicate chronic lymphocytic leukemia, multiple myeloma, Waldenstrom's macroglobulinemia, or Di George syndrome. Decreased T cells may indicate congenital T cell deficiency, Wiskott-Aldrich syndrome, or AIDS. Decreased B cells may indicate acute lymphocytic leukemia or a congenital immunoglobulin deficiency disorder.