Health Topic

Chronic Lymphocytic Leukemia

Chronic Lymphocytic Leukemia or CLL is cancer of the white blood cells, where abnormal cells are made. This makes it hard for the blood to do its work.

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Also called: CLL

Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Chronic Lymphocytic Leukemia

Leukemia is a term for cancers of the blood cells. Leukemia starts in blood-forming tissues such as the bone marrow. Your bone marrow makes the cells which will develop into white blood cells, red blood cells, and platelets. Each type of cell has a different job:

  • White blood cells help your body fight infection
  • Red blood cells deliver oxygen from your lungs to your tissues and organs
  • Platelets help form clots to stop bleeding

When you have leukemia, your bone marrow makes large numbers of abnormal cells. This problem most often happens with white blood cells. These abnormal cells build up in your bone marrow and blood. They crowd out the healthy blood cells and make it hard for your cells and blood to do their work.

Chronic lymphocytic leukemia (CLL) is a type of chronic leukemia. "Chronic" means that the leukemia usually gets worse slowly. In CLL, the bone marrow makes abnormal lymphocytes (a type of white blood cell). When the abnormal cells crowd out the healthy cells, it can lead to infection, anemia, and easy bleeding. The abnormal cells can also spread outside the blood to other parts of the body. CLL is one of the most common types of leukemia in adults. It often occurs during or after middle age. It is rare in children.

CLL happens when there are changes in the genetic material (DNA) in bone marrow cells. The cause of these genetic changes is unknown, so it's hard to predict who might get CLL. There are a few factors that might raise your risk.

It is hard to predict who will get CLL. There are a few factors that could raise your risk:

  • Age - your risk goes up as you get older. Most people who are diagnosed with CLL are over 50.
  • Family history of CLL and other blood and bone marrow diseases
  • Racial/ethnic group - CLL is more common in whites than in people from other racial or ethnic groups
  • Exposure to certain chemicals, including Agent Orange, a chemical that was used in the Vietnam War

In the beginning, CLL does not cause any symptoms. Later, you can have symptoms such as:

  • Swollen lymph nodes - you may notice them as painless lumps in the neck, underarm, stomach, or groin
  • Weakness or feeling tired
  • Pain or a feeling of fullness below the ribs
  • Fever and infection
  • Easy bruising or bleeding
  • Petechiae, which are tiny red dots under the skin. They are caused by bleeding.
  • Weight loss for no known reason
  • Drenching night sweats

Your health care provider may use many tools to diagnose CLL:

  • A physical exam
  • A medical history
  • Blood tests, such as a complete blood count (CBC) with differential and blood chemistry tests. Blood chemistry tests measure different substances in the blood, including electrolytes, fats, proteins, glucose (sugar), and enzymes. Specific blood chemistry tests include a basic metabolic panel (BMP), a comprehensive metabolic panel (CMP), kidney function tests, liver function tests, and an electrolyte panel.
  • Flow cytometry tests, which check for leukemia cells and identify which type of leukemia it is. The tests can be done on blood, bone marrow, or other tissue.
  • Genetic tests to look for gene and chromosome changes

If you are diagnosed with CLL, you may have additional tests to see whether the cancer has spread. These include imaging tests and bone marrow tests.

Treatments for CLL include:

  • Watchful waiting, which means that you don't get treatment right away. Your health care provider regularly checks to see if your signs or symptoms appear or change.
  • Targeted therapy, which uses drugs or other substances that attack specific cancer cells with less harm to normal cells.
  • Chemotherapy
  • Radiation therapy
  • Immunotherapy
  • Chemotherapy with bone marrow or stem cell transplant

The goals of treatment are to slow the growth of the leukemia cells and to give you long periods of remission. Remission means that the signs and symptoms of cancer are reduced or have disappeared. The CLL may come back after remission, and you may need more treatment.

It sits within Cancers, Blood, Heart and Circulation and Immune System.

The lead U.S. institute for this subject is the National Cancer Institute.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Chronic Lymphocytic Leukemia

2,601 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

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Diagnosis and Tests

Treatments and Therapies

Prevention and Risk Factors

Living With

Related Issues

Genetics

Statistics and Research

Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Leukemia, Lymphoid. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Chronic Lymphocytic Leukemia, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.