Testing for CML
The tests that your doctor orders to diagnose and monitor CML are very important. The test results provide information about the phase of the disease and how well you are responding to therapy. This can help you and your doctor make the best treatment decisions for you.
A small sample of blood will be taken from a vein in your arm with a needle. This sample is then sent to a lab for various tests done by a pathologist – a doctor who examines cells under a microscope – or a hematologist, to look for signs of disease.
Bone Marrow Tests:
A small sample of Bone marrow is a soft, spongy material in the centre of most bones, where blood cells are made. A small sample of bone marrow will be removed from your body in two ways:
- A bone marrow aspiration uses a needle to remove some liquid bone marrow (called an “aspirate”) for testing.
- A bone marrow biopsy uses a wider needle to remove a small core of solid bone with marrow inside.
These tests are usually done at the same time, with local anesthetic to numb the surface of the bone. Samples are usually taken from the back of the pelvic bone, but the breastbone can also be used.There are three tests that are used in testing for CML. Over the years, research in this area has yielded great results. Today, a simple blood test is sensitive enough to detect even the smallest trace of the cancer-causing BCR-ABL gene.
Lab tests: what happens next?
Once your blood and bone marrow samples are at the lab, they may be tested in many different ways:
- A complete blood count (CBC) measures the number of white blood cells, red blood cells and platelets in the blood. Renal function and liver enzymes are also measured. In addition, a differential test will be used to check the different types of white blood cells.
- A cytochemistry test uses dyes to help show what type of leukemia cells are in a sample.
- A cell morphology assessment uses a microscope to look at the size, shape, type and maturity of cells.
- Bone marrow cytogenetic testing helps identify the percentage of cells that contain the Philadelphia chromosome responsible for CML.
- Fluorescence in situ hybridization (FISH) testing uses coloured probes to locate the BCR-ABL gene associated with CML.
- Quantitative reverse transcriptase polymerase chain reaction (QPCR) is a more sensitive test that can identify cells with the BCR-ABL gene.
- Flow cytometry is a test used in advanced stages of CML to identify the type and number of leukemia blast cells present.
- BCR-ABL gene mutation analysis looks for new changes to the BCR-ABL gene that may occur during treatment for CML.
- Human leukocyte antigen (HLA) testing identifies proteins that are unique to your blood cells, and is done before a blood stem cell transplant to ensure donor cells match.
Tracking your test results helps show how well your treatment is working. You can keep results in a binder, or click here to use an online tool such as the Leukemia and Lymphoma Society of Canada’s My CML Tracker Pages.