What it is
A complete blood count already tells you.
Every complete blood count (CBC) with differential breaks your white blood cells into types. Neutrophils fight bacteria and are watched closely during chemotherapy, because when they crash you get an infection. Lymphocytes are different: they are the adaptive and innate immune cells, the T cells, B cells and natural killer (NK) cells, that recognize and destroy abnormal cells, including cancer.
The absolute lymphocyte count is the total number of those cells in a microliter of blood. Most labs report it as "Lymphocytes, absolute" or "Lymphs #" in cells/µL or thousands per µL (K/µL), next to a reference range that usually begins somewhere between 850 and 1,000 cells/µL. Below that is called lymphopenia. Ranges vary a little by lab, which is why the printed range on your own report is the one to use.
How to find and read your ALC →