Chronic Myelogenous Leukemia (CML): Diagnosis

If your doctors suspect that you might have chronic myelogenous leukemia (CML), he or she may refer you to a “hematologist,” a physician who specializes in treating blood cancer. The physician will start by taking your medical history and performing a physical examination. As part of the physical examination, your doctor will check for signs of an enlarged spleen. In addition, your doctor may have certain tests performed. These tests may include the following:

• Complete Blood Count (CBC): A sample of blood is drawn from a vein and analyzed for the following:



• number of red blood cells, white blood cells, and platelets
• amount of hemoglobin (the protein that carries oxygen) in the red blood cells
• portion of the sample made up of red blood cells
• appearance of blood cells under the microscope


• Blood chemistry studies: In addition to the CBC, a blood sample may be analyzed to measure the amounts of certain substances released into the blood by the organs and tissues of the body. A higher amount than normal of a particular substance can be a sign of disease in the organ that produces it.



• Peripheral blood smear: This test is used to examine the size, shape, and structure of individual red cells and white cells. A drop of blood is placed on a slide and spread (or “smeared”) over the length of the slide. After the slide dries, it is treated with a special stain so that the cells can be distinguished from one another under the microscope. This is one way in which your medical professionals determine the presence of abnormal “blast” cells in the blood.



• Bone marrow biopsy: If the results of the blood tests indicate a possibility of leukemia, a bone marrow biopsy is typically necessary to confirm the diagnosis. A bone marrow biopsy involves the removal of a tiny piece of bone and bone marrow. The bone and bone marrow samples are usually taken by inserting a hollow needle into the hipbone or breastbone. The samples are then viewed under a microscope to look for abnormal cells.

Special tests are also performed on the biopsy and/or blood samples. These tests are important in confirming a diagnosis and in deciding upon the proper course of treatment for the patient. Some of these tests are described below:

• Immunophenotyping: This test helps to determine the type of disease present. It uses the reaction of antibodies with antigens (proteins) on the cell surface to determine the specific type of cell present.



• Cytogenic analysis: Cytogenic examination is the analysis of the number and shape of the chromosomes of cells. The medical professional who performs this analysis is called a “cytogeneticist.” The cytogeneticist views cells from a sample of blood or bone marrow under a microscope to look for changes in the chromosomes, such as the Philadelphia chromosome. This test is very helpful in diagnosing the specific type of leukemia, determining the course of treatment, and in following the response to the treatment administered.

This Web site is sponsored by the law firm of Baron & Budd, P.C. Please understand that the information provided is not medical advice, but is simply offered as a resource to help you learn about chronic myelogenous leukemia (CML) and benzene. Please discuss your health-related questions and concerns with your doctor.

Benzene can cause chronic myelogenous leukemia and other blood cancers and disorders. If you have been diagnosed with CML leukemia and would like information about your legal rights, please call us at 800-946-9646 or e-mail us at

Please also visit our glossary for helpful definitions of medical terms relating to the diagnosis and treatment of CML.