The short answer
CLL is staged using the Rai system (common in the US) or the Binet system (common in Europe), both based on blood counts and physical exam findings rather than imaging. Higher stages reflect anemia or low platelets, not just how much lymph tissue is enlarged.
CLL uses two staging systems: Rai (more common in the United States) and Binet (more common in Europe). Both use blood counts and a physical exam, not imaging scans.
In the Rai system, stages range from 0 (low risk) to IV (high risk); in Binet, stages range from A (low risk) to C (high risk).
The highest-risk stages in both systems are defined by anemia and/or low platelet counts, not simply by how many lymph node areas are enlarged.
Stage at diagnosis is one input into the decision about when to start treatment; many people at an early stage are monitored rather than treated right away.
Choose how you want to understand this
The full explanation.
The simple version
CLL doesn't have the size-and-spread staging used for many solid tumors. Instead, it is staged using blood counts and a physical exam, through one of two systems: Rai, used more often in the United States, or Binet, used more often in Europe. Both describe how much the disease is currently affecting the blood and body.
CLL staging is built from blood counts and a physical exam, not from a scan measuring tumor size.
The Rai system
- Stage 0 (low risk): High lymphocyte count (lymphocytosis) only; lymph nodes, spleen, and liver are not enlarged; red blood cell and platelet counts are near normal.
- Stage I (intermediate risk): Lymphocytosis with enlarged lymph nodes; spleen and liver not enlarged; red blood cell and platelet counts near normal.
- Stage II (intermediate risk): Lymphocytosis with an enlarged spleen and/or liver; lymph nodes may or may not be enlarged; red blood cell and platelet counts near normal.
- Stage III (high risk): Lymphocytosis, with or without enlarged lymph nodes, spleen, or liver; red blood cell counts are low (anemia); platelet counts near normal.
- Stage IV (high risk): Lymphocytosis with enlarged lymph nodes, spleen, or liver; red blood cell counts may be low or near normal; platelet counts are low (thrombocytopenia).
The Binet system
- Stage A (low risk): Fewer than three enlarged lymphoid areas; no anemia or low platelets.
- Stage B (intermediate risk): Three or more enlarged lymphoid areas; no anemia or low platelets.
- Stage C (high risk): Anemia and/or thrombocytopenia is present, regardless of how many lymphoid areas are enlarged.
What both systems have in common
Notice that the highest-risk category in each system is defined by anemia or low platelets, not simply by how many places are physically enlarged. This reflects a key idea in CLL: the disease becomes more urgent when it starts crowding out normal blood cell production in the bone marrow, not just when it's more "spread out."
Stage is not the whole picture
Stage tells your team how the disease currently looks in your blood and exam. It does not, by itself, capture the genetic features of your CLL cells, which also strongly affect prognosis and treatment choice. Two genetic markers commonly tested alongside stage are:
- IGHV mutation status: mutated status is generally linked to slower-behaving disease
- del(17p) or TP53 mutation status: linked to a higher-risk, harder-to-treat course
Ask your team to walk through your stage and these markers together, since they answer different questions.
Early stage doesn't always mean immediate treatment
Many people diagnosed at Rai stage 0–I or Binet stage A are not treated right away. This is watch and wait, a deliberate, monitored approach used because trials have not shown that treating early-stage, symptom-free CLL sooner improves how long people live. See Blood Cancer and the Watch and Wait Approach.
Questions to ask
- What is my Rai or Binet stage, and what specifically puts me there?
- What are my IGHV and del(17p)/TP53 results?
- Am I being monitored, or is treatment starting now, and why?
- What would move me to a higher stage or trigger treatment?
Sources
Words to know
Tap any term to see what it means.
Common questions
Why does CLL use blood counts to stage, instead of a scan?
CLL is a cancer of the blood and lymph system, already circulating through the body at diagnosis, so a size-and-spread staging system built for solid tumors doesn't fit well. Instead, Rai and Binet staging use lymphocyte counts, physical exam findings (lymph nodes, spleen, liver), and whether anemia or low platelets are present, which together predict how the disease is behaving.
What's the difference between the Rai and Binet systems?
They measure similar things using different stage labels. Rai uses numbers 0 through IV and is used more often in the United States. Binet uses letters A through C, based on how many lymphoid areas (such as lymph node regions, spleen, and liver) are enlarged, and whether anemia or low platelets are present. Your care team may reference either, or convert between them.
Does a low stage mean I don't have "real" CLL?
No. Every stage is CLL. Stage in this system reflects how much the disease is currently affecting your blood counts and body, which relates to prognosis and timing of treatment, not whether the diagnosis is real or serious.
If I'm at an early stage, will I be treated right away?
Often not immediately. Randomized trials have not shown a survival benefit to treating early-stage, symptom-free CLL right away compared with monitoring. Many people at Rai stage 0–I or Binet stage A are followed with watch and wait until specific triggers appear.
Why do I also need genetic testing if I already have a stage?
Stage describes how the disease looks right now, in your blood counts and exam findings. Genetic and molecular markers, such as IGHV mutation status and del(17p) or TP53 status, add information about how the CLL is likely to behave over time and which treatments are likely to work best. Doctors use stage and these markers together.
Questions to ask your doctor
Being prepared helps you get the most out of your appointments. Save or print these questions.
Tap a question to save it to your list (kept on this device).
Speak With Trained Specialists & Human Navigators
Cancer Explained provides educational guidance, but does not replace trained specialists, social workers, or your medical team.
Talk to a trained cancer information specialist
Free, confidential assistance from NCI Cancer Information Service via phone, chat, or email.
Contact your oncology team
Locate after-hours contact numbers, portal messages, or urgent triage phone lines.
Find a patient navigator
Get one-on-one help with appointments, logistics, translation, and care coordination.
Find a genetic counselor
Discuss inherited mutation risk, family history, and genetic testing options.
Find an oncology social worker
Access emotional counseling, family support groups, and mental health resources.
Find a financial navigator
Locate copay assistance foundations, grant programs, and lodging/travel support.
Find a clinical-trial specialist
Search matching studies and speak with NCI trial information specialists.
Get urgent help
Immediate emergency guidance for fever (>100.4°F during chemo), severe pain, or shortness of breath.
Help Us Improve This Guide
Did this explanation answer your question and help you determine your next step?
Know someone who needs this?
Plenty of people are looking for something like this and do not know where to start. If this would help a friend or someone you love, send it on — we have written an opening line so you do not have to stare at an empty message. You can change every word of it.
Your message is written and sent in your own email or messaging app — we never see who you send it to, and nothing is added to any list.
Plain-language explanation of the federal sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.
Last updated: 2026-08-03Next planned review: 2027-08-03
How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status — Source verified. This page was created with AI assistance and checked against the sources listed on it. Source checking is not a medical review.
General education — varies by person. Answers genuinely differ between people. This page explains what commonly varies and points you to your care team for your situation.
Human medical review: not completed. Cancer Explained is not clinician-reviewed, and that is a deliberate design choice rather than a gap we are waiting to close. We restate published federal guidance and cite it; the authority belongs to the source, not to us. That is why every page names where its claims come from — so you can verify us instead of trusting us. Use it to understand your situation and to ask better questions of the people treating you.
How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source verified — This page was created with AI assistance and checked against the sources listed on it. Source checking is not a medical review.
Human medical review: not completed. Cancer Explained is not clinician-reviewed, and that is a deliberate design choice rather than a gap we are waiting to close. We restate published federal guidance and cite it; the authority belongs to the source, not to us. That is why every page names where its claims come from — so you can verify us instead of trusting us. Use it to understand your situation and to ask better questions of the people treating you.
Read more about our editorial process, our use of AI, and our corrections policy.
Spotted a problem? Report an error — a factual mistake, broken or outdated source, confusing wording, or anything that seems unsafe. Please do not include names, medical record numbers, dates of birth, addresses, or other identifying medical information in your report.
After using this page, do you understand what to do next?
Anonymous — we only record the answer, never who gave it.
Related articles
Still have questions?
Educational answers, plain language
Free to print and share