System used for clinical staging of chronic lymphocytic leukemia. Stage 0-lymphocytosis alone (> 15,000/?1 in peripheral blood, > 40% marrow lymphocytosis); stage IÑlymphocytosis and enlarged nodes; stage IIÑlymphocytosis and splenomegaly and/or hepatomegaly; stage IIIÑlymphocytosis and anemia (hemoglobin < 11 g/dl); stage IVÑlymphocytosis and thrombocytopenia (platelets < 100,000/?1).