Chronic Lymphocytic Leukemia (CLL): Diagnosis 

How is chronic lymphocytic leukemia (CLL) diagnosed?

If your healthcare provider thinks you might have CLL, you will need certain exams and tests to make sure. Your healthcare provider will ask you about your health history, your symptoms, risk factors, and family history of disease. Your healthcare provider will also give you a physical exam.

What tests might I need?

You may have 1 or more of these tests:

  • Blood tests.  CLL is often found with blood tests before a person has symptoms. Tests can look at the numbers of each type of blood cell. People with CLL often have way too many white blood cells (WBCs). Details can show which kind of WBC is increased. It's usually lymphocytes.

  • Bone marrow aspiration or biopsy. This procedure is done by taking out a small amount of bone marrow (aspiration) and/or solid bone marrow tissue (core biopsy). The sample is taken from the back of the hip (pelvic) bone. For the bone marrow aspiration, the skin over the hip is numbed. A long, hollow needle is pushed into the pelvic bone. A syringe is used to pull out a small amount of liquid bone marrow. You may have some brief pain when the marrow is removed. A bone marrow biopsy is usually done just after the aspiration. A slightly bigger needle is used to take out a small core of bone and marrow. This may also cause some brief pain. The fluid and bone marrow are sent to a lab and tested for the number, size, and maturity of the blood cells and checked for abnormal cells. Other tests can also be done on these cells but they're not usually needed to diagnose CLL. 

How blood or bone marrow is tested

Tests can be done on blood (or less often, bone marrow) samples to diagnose CLL and help get an idea of how quickly it's likely to grow. The tests include:

  • Flow cytometry and immunohistochemistry.  These tests use chemicals and dyes to look for certain proteins on the surface of the leukemia cells. This is called immunophenotyping.

  • Cytogenetics. These tests look for changes in the chromosomes of cells. It can be done on samples of blood, bone marrow, or lymph nodes. For instance, in CLL, part of a chromosome may be missing or there may be extra copies of a chromosome. This test usually takes a few weeks because the cells need time to be grown in the lab.

  • Fluorescent in situ hybridization (FISH). This test uses special fluorescent dyes that only attach to certain parts of chromosomes. It can be used to look for certain changes in genes and chromosomes that are found in CLL cells from blood or bone marrow samples. The FISH test is very accurate and gives results more quickly than standard cytogenetic tests.

Getting your test results

When the results of your tests are in, your healthcare provider will contact you to discuss them. He or she will also talk with you about other tests you may need if CLL is found. Make sure you understand the results of your tests and what follow-up you need.

News & Publications

Quantity and Characteristics of Waste at a Level I Trauma Center

The purpose of this study was to quantify and describe the amount of waste generated by an Emergency Department, identify deviations from waste policy and explore areas for waste reduction.

The Climate-Smart Emergency Department: A Primer

Our publication keeps health care professionals up to date on the latest research and clinical advances from Mass General.

Research Institute Blog

News and notes from the largest hospital-based research program in the United States


A podcast devoted to uncovering the stories of Mass General's relentless pursuit to break boundaries and provide exceptional care