The CLL medical abbreviation stands for chronic lymphocytic leukemia, a cancer of B lymphocytes, the white cells that make antibodies. The abnormal cells build up slowly in the blood, bone marrow and lymph nodes, and many people live with the condition for years before it needs treatment.
If you searched for the medical term for CLL, that full name is the answer, and the acronym is used in nearly every note that follows. It is the most common leukemia in adults in many Western countries and is found mostly in older people. Often it turns up on a routine blood count before any symptoms. This page explains each word in the name, the tests you may see, and the chart phrases, like watch and wait, that confuse many patients.
At a glance
Stands for
Chronic lymphocytic leukemiaCell involved
B lymphocytes, a kind of white blood cellClose relative
SLL, small lymphocytic lymphoma, the same disease mainly in lymph nodesSpecialty
Hematology and oncologyCommon first clue
High lymphocyte count on a CBCDo not confuse with
AML and CML, different leukemiasCLL medical acronym
Also written as medical abbreviation CLL in problem lists
The CLL medical abbreviation, one word at a time
Chronic means it develops and progresses slowly, in contrast to acute leukemias that move quickly. Lymphocytic means it involves lymphocytes, white blood cells that help fight infection. Leukemia comes from Greek words meaning white blood, because cancers of white cells were first noticed by how they changed the look of blood.
In CLL, a single family of B lymphocytes grows out of control. These cells look fairly mature under the microscope but do not work well, and over time they crowd out healthy blood cells. That can lead to swollen lymph nodes, an enlarged spleen, anemia, low platelets and more infections, though many people have none of these at diagnosis.
How it is found and confirmed
The first hint is usually a raised absolute lymphocyte count on a complete blood count ordered for something else. To confirm it, a lab runs flow cytometry on a blood sample, which reads markers on the surface of the cells and shows that they all come from one clone with the pattern typical of CLL.
Further tests help estimate how the disease may behave. These can include genetic tests on the leukemia cells and markers that predict how fast it may grow. Doctors also use staging systems based on the blood counts and physical exam findings such as enlarged nodes, liver or spleen. A bone marrow biopsy is not always needed.
Decoding watch and wait in a note
Hematology note: "CLL, early stage, ALC 18K, Hgb and Plt normal. No B symptoms. Continue active surveillance, CBC q3 months." ALC is the absolute lymphocyte count, here about 18,000 per microliter. Hgb is hemoglobin and Plt is platelets. B symptoms are fevers, night sweats and weight loss. Active surveillance means the team will keep checking without starting treatment yet. The interval is an example of format only.
Many patients are surprised that a cancer diagnosis does not lead straight to treatment. For early CLL without symptoms, studies have shown that starting treatment early does not help people live longer, so doctors watch closely and begin therapy when certain signs appear, such as falling blood counts, bulky nodes or troubling symptoms.
CLL compared with other leukemia abbreviations
Leukemias are named by speed, chronic or acute, and by the cell line involved, lymphoid or myeloid.
| Abbreviation | Full name | Typical pace |
|---|---|---|
| CLL | Chronic lymphocytic leukemia | Slow |
| CML | Chronic myeloid leukemia | Slow at first |
| ALL | Acute lymphoblastic leukemia | Fast |
| AML | Acute myeloid leukemia | Fast |
Be careful with ALL, which in a medication or allergy context can look like the plain word all. CLL can also, rarely, change into a faster growing lymphoma such as DLBCL, which notes may call transformation.
When treatment begins
When treatment is needed, modern options include targeted pills that block signals the leukemia cells depend on, antibody infusions that mark the cells for destruction, and older chemotherapy combinations for some patients. The choice depends on genetic features of the leukemia, age, other health conditions and personal preference.
People with CLL also tend to have weaker immune defenses, so their teams pay close attention to vaccines and infections. Notes may mention immunoglobulin levels, which show how many antibodies the body is making.
Questions to ask your hematologist
- What stage is my CLL, and what do my genetic test results suggest?
- During surveillance, what schedule of blood tests do you plan?
- Which symptoms should make me call before my next visit?
- Which vaccines are recommended for me?
For other blood and cancer short forms, such as MGUS or MDS, see the conditions and diagnoses hub.
Outlook and treatment timing in CLL differ a great deal between people. Ask your hematology team how your own results fit that range.
Frequently asked questions
What is the medical term for CLL?
The medical term is chronic lymphocytic leukemia. It is a slow growing cancer of B lymphocytes, a type of white blood cell.
Is CLL the same as SLL?
They are considered the same disease. When the abnormal cells are mostly in the blood it is called CLL, and when they are mostly in the lymph nodes it is called small lymphocytic lymphoma, or SLL.
Why is CLL sometimes not treated right away?
In early CLL without symptoms, starting treatment early has not been shown to help people live longer. Doctors monitor blood counts and symptoms and begin treatment when specific signs appear.
What does ALC mean in a CLL note?
ALC stands for absolute lymphocyte count, the number of lymphocytes in a given volume of blood. It is one of the numbers tracked over time in CLL.
Is CLL hereditary?
Having a close relative with CLL raises the chance somewhat, but most relatives never develop it. Your hematologist can explain what family history means in your case.