Chronic Myeloid Leukemia (CML): Diagnosis 

How is chronic myeloid leukemia (CML) diagnosed?

If your healthcare provider thinks you might have CML, 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. Blood is taken from the arm or hand with a needle. The blood is then tested in various ways (see below).

  • Bone marrow aspiration and biopsy. This procedure is done by taking small amounts of bone marrow. Bone marrow samples are usually taken from the back of the hip (pelvic) bone. For the bone marrow aspiration, the area over the hip is numbed. A thin, hollow needle is inserted into the hip 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 small piece of bone and marrow is removed with a slightly larger needle that is pushed down into the bone. The biopsy may also cause some brief pain. The bone marrow is then checked for leukemia cells and tested in various ways (see below).

How blood or bone marrow is tested 

Nearly all cases of CML have cells with the Philadelphia chromosome and an abnormal gene called BCR-ABL. People with CML also have too many white blood cells. The tests done on blood or bone marrow samples may include:                                                                                                                                                            

  • Complete blood count (CBC). This test measures the numbers of different types of cells in the blood. This test can show if a person has too many white blood cells.

  • Cytogenetics. For this test, cells are grown in a lab for a week or more. The chromosomes inside the cells are then stained with special dyes and viewed with a microscope. Major problems in the chromosomes can often be seen with this test. But smaller changes may not be visible.

  • Fluorescence in situ hybridization (FISH). This test is another way to look for changes in chromosomes. The cells in the sample are stained with fluorescent dyes that will only attach to certain parts of chromosomes. The cells are then viewed with a microscope using a special light. This test can find some chromosome changes that can't be seen with standard cytogenetic testing. It is also a quicker test. Many medical centers now use this test.

  • Polymerase chain reaction (PCR). This is a very sensitive test that can detect very low levels of leukemia cells in a test sample. It works by increasing the amount of genetic material in a sample so that it can be detected. This test can find small levels of chromosome changes that other tests can’t find.  

Getting your test results

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