Diagnosis of chronic lymphocytic lymphoma (CLL)/small lymphocytic lymphoma (SLL) will be made according to the World Health Organization (WHO) diagnostic classification. A lymphocyte count in excess of 5000/mcl is typically found in the leukemic variant but is not a pre-requisite for a diagnosis of SLL. Low, Intermediate or High-Risk Category of CLL/SLL, using the Modified Three-Stage Rai Staging System as follows: