Rai Staging System

**Semantic type:** Classification

**Definition:** A staging system for Chronic Lymphocytic Leukemia. Stage 0: absolute lymphocytosis (>15,000 per cubic millimeter) without adenopathy, hepatosplenomegaly, anemia, or thrombocytopenia; Stage I: absolute lymphocytosis with lymphadenopathy without hepatosplenomegaly, anemia, or thrombocytopenia; Stage II: absolute lymphocytosis with either hepatomegaly or splenomegaly, with or without lymphadenopathy; Stage III: absolute lymphocytosis and anemia (hemoglobin <11 g/dL) with or without lymphadenopathy, hepatomegaly, or splenomegaly; Stage IV: absolute lymphocytosis and thrombocytopenia (<100,000 per cubic millimeter) with or without lymphadenopathy, hepatomegaly, splenomegaly, or anemia. (from OncoLink)