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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 be 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 one or more of the following tests:

  • Blood tests. CLL is often found with blood tests before a person has symptoms. Tests can look at the numbers of different types of blood cells. People with CLL often have too many lymphocytes. This is a type of white blood cell.

  • Bone marrow aspiration and/or biopsy. This procedure is done by taking a small amount of bone marrow fluid (aspiration) and/or solid bone marrow tissue (core biopsy). This is most often done from the hip bones. The fluid and bone marrow are examined for the number, size, and maturity of blood cells and abnormal cells. Other tests can also be done on these cells. These procedures are not usually needed to diagnose CLL, which can often be done just with blood tests. But they may be done before treatment to help see how fast the leukemia is likely to grow. 

How blood or bone marrow is tested

Tests can be done on blood or bone marrow samples to diagnose CLL and help determine how quickly it is likely to grow. The tests include:

  • Flow cytometry and immunohistochemistry. These tests are used on blood, bone marrow, or other biopsy samples. The tests look for certain substances on the surface of the leukemia cells. This is called immunophenotyping. These tests can be used to make the diagnosis of CLL. Flow cytometry can also be used to test blood for substances called ZAP-70 and CD38. These may be able to tell what type of B lymphocyte the leukemia is growing in.

  • Cytogenetics. These tests look for changes in the chromosomes of cells from samples of blood, bone marrow, or lymph nodes. For example, in some cases of CLL, part of a chromosome may be missing. This test usually takes a few weeks. This is because the cells need time to be grown in the lab. Because of this, it’s not used as often anymore.

  • Fluorescent in situ hybridization (FISH). This is a type of cytogenetic test. It uses special fluorescent dyes that only attach to certain parts of chromosomes. It can be used to look for changes in chromosomes that are found in blood or bone marrow samples. It doesn’t need cells to grow in the lab first. The FISH test is very accurate and gives results more quickly than standard cytogenetic tests. This is why it’s now used in many medical centers.

Getting your test results

When your healthcare provider has the results of your tests, he or she will contact you with the results. Your healthcare provider will talk with you about other tests you may need if CLL is found. Make sure you understand the results and what follow-up you need.

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