The Rai staging system, either the classic or the modified version, is more commonly used in North America. There is another staging system called Binet staging that is used in Europe. Both classify CLL and assign risk categories based on:
- Number of lymphocytes found in the blood;
- Enlargement of the lymph nodes, liver and spleen;
- Number of platelets found in the blood;
- Number of red blood cells found in the blood).
* A high lymphocyte count is defined as more than 15,000 lymphocytes per cubic millimeter (> 15,000/mm3)