Rai staging for chronic lymphocytic leukaemia
Clinical staging (0–IV) by lymphadenopathy, organomegaly and cytopenias, grouped into three risk levels.
Switch how results are explained
Rai stage 0 (low risk): blood and marrow lymphocytosis only. Watch and wait is standard.
- Evidence grade
- A
What it is and when to use it
Rai staging assumes blood and bone marrow lymphocytosis and adds findings in order of progression: stage 0, lymphocytosis only; I, enlarged lymph nodes; II, splenomegaly and/or hepatomegaly; III, anaemia (Hb < 11 g/dL); IV, thrombocytopenia (platelets < 100 ×10⁹/L). The stage is that of the most advanced finding, whether or not those of lower stages are present.
How to interpret it
The modified Rai system groups the stages into low risk (0), intermediate risk (I–II) and high risk (III–IV). Early stages are monitored without treatment unless the disease is active by iwCLL criteria; high-risk stages generally warrant treatment. In the original 1975 series, median survival was over 150 months in stage 0 and 19 months in stages III and IV.
Limitations and when not to use it
Applies only to an already-diagnosed chronic lymphocytic leukaemia. Anaemia or thrombocytopenia counts towards the stage only when it is due to marrow infiltration, not to autoimmune haemolysis, immune thrombocytopenia or another cause. The survival figures predate current treatments, and the stage alone does not decide treatment.
Formulas and cut-offs are from the original authors of each score; see the references.
Last reviewed: June 2026
References
- Rai KR, Sawitsky A, Cronkite EP, Chanana AD, Levy RN, Pasternack BS. Clinical staging of chronic lymphocytic leukemia. Blood. 1975;46(2):219-234. PMID:1139039
- Hallek M, Cheson BD, Catovsky D, et al. iwCLL guidelines for diagnosis, indications for treatment, response assessment, and supportive management of CLL. Blood. 2018;131(25):2745-2760. PMID:29540348