Leukemia - Chronic Myeloid - CML: Diagnosis

Approved by the Cancer.Net Editorial Board, 11/2016

ON THIS PAGE: You will find a list of common tests, procedures, and scans that doctors use to find the cause of a medical problem. To see other pages, use the menu.

Doctors use many tests to find, or diagnose, leukemia. They also do tests to learn more about the extent of the disease. Doctors may also do tests to learn which treatments could work best.

For most types of cancer, a biopsy is the only sure way for the doctor to know whether an area of the body has cancer. In a biopsy, the doctor takes a small sample of tissue for testing in a laboratory. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis.  

This list describes options for diagnosing CML, and not all tests listed will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:

  • The type of leukemia suspected

  • Your signs and symptoms

  • Your age and medical condition

  • The results of earlier medical tests

The following tests may be used to diagnose or monitor CML:

  • Blood tests. Many people are diagnosed with CML through a blood test called a complete blood count (CBC) before they have any symptoms. A CBC counts the number of different kinds of cells in the blood. A CBC is often done as part of a regular medical checkup. People with CML have high levels of white blood cells. However, white blood cell levels might also be caused by conditions that are not leukemia. When the CML is more advanced, there may also be low levels of red blood cells, a condition called anemia, and either elevated or decreased numbers of platelets.

  • Bone marrow aspiration and biopsy. These 2 procedures are similar and often done at the same time to examine the bone marrow. Bone marrow has both a solid and a liquid part. A bone marrow aspiration removes a sample of the fluid with a needle. A bone marrow biopsy is the removal of a small amount of solid tissue using a needle.

    A pathologist then analyzes the sample(s). A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease. A cytogenetic analysis (see below) may also be done on the marrow samples. A common site for a bone marrow aspiration and biopsy is the iliac crest of the pelvic bone (see the Medical Illustrations section), which is located in the lower back by the hip. The skin in that area is usually numbed with medication beforehand, and other types of anesthesia (medication to block awareness of pain) may be used.

  • Molecular testing. Your doctor may recommend testing the leukemia cells for specific genes, proteins, and other factors unique to the leukemia. Results of these tests will help determine whether your treatment options include a type of treatment called targeted therapy (see the Treatment Optionssection).

    Cytogenetics is a type of genetic testing that is used to analyze a cell’s chromosomes. It looks at the number, size, shape, and arrangement of the chromosomes. Occasionally, this test can be done on the peripheral or circulating blood when the CML is first diagnosed, but immature blood cells that are actively dividing need to be used. Because of this, a bone marrow sample (see above) is usually the best way to get a sample for testing.

    After treatment begins, cytogenetic and/or molecular testing is repeated on another bone marrow sample to find out if there are fewer cells with the Philadelphia chromosome. For most people with CML, the Philadelphia (Ph+) chromosome and the BCR-ABL fusion gene (described in the Introduction section) can be found through testing, which confirms the diagnosis. For a small number of patients, increased blood cell counts may suggest CML, but the Philadelphia chromosome cannot be found on the usual tests even though the BCR-ABL fusion gene is there. Treatment for these patients is the same and works as well as it does for patients with a detectable Philadelphia chromosome.

    Cytogenetic testing for CML is used to monitor how well treatment is working and if it is reducing the number of cells with the Philadelphia chromosome. The following tests are sometimes used with cytogenetic testing:

    • Fluorescence in situ hybridization (FISH) is a test used to detect the BCR-ABL gene and to monitor the disease during treatment. This test does not require dividing cells and can be done using a blood sample or bone marrow cells. This test is a more sensitive way to find CML than the standard cytogenetic tests that identify the Philadelphia chromosome.

    • Polymerase chain reaction (PCR) is a DNA test that can find the BCR-ABL fusion gene and other molecular abnormalities. PCR tests may also be used to monitor how well treatment is working. This test is quite sensitive and, depending on the technique used, can find 1 abnormal cell mixed in with approximately 1 million healthy cells. This test can be done using a blood sample or bone marrow cells.

  • Imaging tests. Doctors may use imaging tests to find out if the leukemia is affecting other parts of the body. For example, a computed tomography (CT or CAT) scan or ultrasound examination is sometimes used to look at and measure the size of the spleen in patients with CML.

    • A CT scan creates a 3-dimensional picture of the inside of the body using x-rays taken from different angles. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities. Sometimes, a special dye called a contrast medium is given before the scan to provide better detail on the image. This dye can be injected into a patient’s vein or given as a liquid to swallow.

    • An ultrasound uses high-frequency sound waves to create a picture of the inside of the body.

After diagnostic tests are done, your doctor will review all of the results with you. If the diagnosis is CML, these results also help the doctor describe the phase of the disease.

The next section in this guide is Phases. It explains the system doctors use to describe the extent of the disease. Or, use the menu to choose another section to continue reading this guide.