Get our free guide, Chronic Myeloid Leukemia (CML): In Detail
This booklet on CML includes a glossary of terms and details on what to expect during each stage of diagnosis, treatment, and follow-up care.
Download or order up to 50 free copies today.
Many people with chronic myeloid leukemia (CML) do not have symptoms when diagnosed. The most common sign of CML is an abnormal white blood cell count, often found during blood tests for an unrelated health problem or during a routine checkup. To diagnose CML, doctors use a variety of tests to analyze blood and bone marrow cells. A pathologist, a doctor who specializes in identifying diseases by studying cells under a microscope, will examine the blood and bone marrow cells. The samples should also be examined by a hematopathologist, a specialist who diagnoses diseases of the blood and marrow.
The information on this page covers how CML is diagnosed in adults. Visit CML in children and young adults to learn about signs and symptoms, diagnosis, and treatment information for children and young adults with CML.
Tests your doctor may use to diagnose CML
Your doctor may use the following tests to diagnosed CML:
Blood and bone marrow tests
Blood tests measure the number of red and white blood cells and platelets in the blood. Bone marrow tests measure the fluid and tissue in your marrow. Open each section below to learn more.
This test is used to measure the number red blood cells, white blood cells, and platelets in a sample of blood. It also measures the amount of hemoglobin in the red blood cells and the percentage of red blood cells in the sample. The CBC should include a differential, which measures the different types of white blood cells in the sample.
People with CML often have the following blood characteristics:
- An increased white blood cell count, often a very high level
- A decreased red blood cell count
- A possible increase or decrease in the number of platelets, depending on the severity of the disease
These two tests are used to examine bone marrow cells to find abnormalities and are generally done at the same time. The sample is usually taken from the patient’s hip bone after medicine has been given to numb the skin.
For a bone marrow aspiration, a hollow needle is inserted through the hip bone and into the bone marrow to remove a liquid sample of cells. For a bone marrow biopsy, a wider needle is used to remove a small piece of bone that contains marrow. Both samples are examined under a microscope to look for chromosomal and other cell changes.
Learn more about bone marrow tests.
View the interactive 3D model to help you visualize and better understand the procedure. Click the "Interact in 3D" button to begin.
Biomarker testing
The following tests are used to identify, examine, and measure chromosomes and genes. Open each section below to learn more.
Cytogenetics is the study of chromosomes and chromosomal abnormalities. In these tests, special stains are applied to a bone marrow sample and then the cells are examined for chromosomal changes or abnormalities, such as the Philadelphia (Ph) chromosome.
The presence of the Ph chromosome in the bone marrow cells, along with a high white blood cell count and other characteristic blood and bone marrow test findings, confirm the diagnosis of CML.
In about 95 percent of people with CML, the Ph chromosome in bone marrow cells is detectable by cytogenetic analysis. In a small percentage of people with clinical signs of CML, the Ph chromosome cannot be detected by cytogenetic analysis. However, these patients almost always test positive for the BCR::ABL1 fusion gene on chromosome 22, found with the other types of tests, such as FISH and qPCR (see below).
This laboratory test is used to examine genes and chromosomes in cells. It is a slightly more sensitive method for detecting CML than the standard cytogenetic tests used to identify the Ph chromosome. FISH tests can identify the presence of the BCR::ABL1 gene.
The qPCR test is the most sensitive test used to detect and measure the quantity of the BCR::ABL1 gene in blood or bone marrow samples. It can detect very small amounts of the BCR::ABL1 gene, even when the Ph chromosome cannot be detected in blood or bone marrow cells with cytogenetic testing. It is capable of detecting one CML cell among 100,000 normal cells.
Learn what doctors and patients say about the value of PCR testing.
CML phases and prognostic factors
CML has three phases. The phase of your CML plays a large part in determining the type of treatment you'll receive. Doctors use diagnostic tests to determine the phase of CML. Determining the CML phase is based primarily on the number of immature white blood cells (blasts) in the patient’s blood and bone marrow.
Chronic phase: Most patients are diagnosed with CML in the chronic phase of the disease. People with chronic phase CML may or may not have symptoms, but generally have an increased number of white blood cells and usually respond well to standard treatment.
If untreated, chronic phase CML will eventually progress to accelerated phase CML and/or blast phase CML.
Accelerated phase: The number of leukemia cells in the blood and bone marrow is higher than in chronic phase CML. People with accelerated phase CML may have symptoms such as fever, weight loss, fatigue (extreme tiredness), bone pain, and night sweats. If CML is not treated, it will progress to the next, more serious, blast phase.
Blast phase (or "blast crisis phase"): The number of leukemia cells in the blood and bone marrow is higher than in accelerated phase CML. People who have blast phase CML may have symptoms such as fever, fatigue, shortness of breath, abdominal pain, bone pain, enlarged spleen, poor appetite and weight loss, night sweats, bleeding, and/or infections. The blast phase appears and behaves like acute myeloid leukemia (AML).
Prognostic factors of CML
There are other factors, in addition to the phase of CML, that affect treatment decisions and can be used to predict a patient’s prognosis. These are called “prognostic factors.”
The following prognostic factors for patients with CML at the time of diagnosis are also associated with a less favorable prognosis:
- Being in the accelerated or blast phase CML, as opposed to chronic phase CML
- Being 60 years and older
- Having an enlarged spleen
- Having very high or very low platelet counts at diagnosis
- Having a high number of blasts in the blood
- Having an increased numbers of basophils
Many of these factors are used in prognostic scoring systems to predict outcomes for patients with CML. There are three prognostic scoring systems used to determine the risk profile of patients with chronic phase CML at the time of diagnosis:
- Sokal scoring system
- Hasford (Euro) scoring system
- European Treatment and Outcome Study for CML (EUTOS) Long-Term Survival scoring system (ELTS)
Learn more about these scoring systems in our free booklet, Chronic Myeloid Leukemia: In Detail.
Get free, one-on-one support
Call, email, or chat with a member of our highly trained support team.
Blood Cancer United resources
Find free, specialized guidance and information for every type of blood cancer, request financial support, find emotional support, and connect with other members of the blood cancer community.
