Tests for chronic myeloid leukaemia (CML)

You usually have a number of tests to check for chronic myeloid leukaemia (CML). Your doctor may suspect or sometimes diagnose leukaemia from a blood test. You then might have more tests to confirm your diagnosis and find out more about the type of leukaemia you have.

CML is a type of blood cancer. It starts from blood cells called myeloid ​stem cells​ in the bone marrow. The bone marrow is the soft inner part of the bones where new blood cells are made.

CML is different from acute myeloid leukaemia (AML). AML tends to develop quickly and gets rapidly worse if it is not treated. CML usually develops very slowly.

We have separate information about the tests you might have for AML and other types of leukaemia.

Find out about the tests for other types of leukaemia

Tests your GP might do

CML tends to develop slowly, so most people don’t have any symptoms. People are often diagnosed after having a routine blood test for something else.

Find out about the possible symptoms of CML

If you see your GP, they might do some tests to help them decide if you need to see a specialist. The tests they might do include:

• physical examination

• blood tests

Depending on the results of your examination and blood tests, your GP may also arrange for you to have other tests such as an x-ray or ultrasound scan. You usually have these tests at your local hospital.

Read about what to expect when you see your GP

Physical examination

Your doctor usually asks you to lie or sit down. They look at and feel your skin all over your body to check for any abnormalities or areas that are swollen. Things they look for include signs of bleeding, bruising and infection.

They may also listen to your chest and tummy (abdomen) to find out if they sound normal.

You can ask for someone else to be in the room with you if you want, to act as a chaperone. A chaperone is a trained healthcare professional such as a nurse. A friend or relative can also stay with you for support. They can be with you during the examination.

Tests your specialist might do

If your GP thinks you have leukaemia they'll arrange for you to go to the hospital. Sometimes this is quite quick, and you might have to go there straight away.

The specialist you see at the hospital is called a haematologist. This is a doctor who specialises in diseases of the blood.

Your specialist usually does more tests and repeats the blood tests done by your GP. The other tests might include:

• different laboratory tests to look for changes in the ​genes​  and ​chromosomes​ of your leukaemia cells

• a bone marrow test

• a test to check for certain proteins (immunophenotyping)

• tests for infections

• an x-ray

• an ultrasound scan

• tests for tissue typing

FISH (fluorescence in situ hybridisation)

FISH testing looks at gene and chromosome changes. Genes are found on chromosomes within all cells. They tell the cell which proteins to make.

A FISH test is usually the first ​genetic​ test that you have. 

The FISH technique uses a fluorescent dye that glows up under a special microscope. The dye tags specific genes.

For this test scientists label specfic genes with a green and red dye. In this case they label the BCR gene and ABL1 gene. When these 2 genes join they make the BCR-ABL1 gene. Under the microscope this is picked up as the join turns yellow. This gene change helps your doctor diagnose CML.

This test is usually done first as the process is quicker than other tests used to pick up chromosome and gene changes.

You may also have FISH testing alongside other tests to help work out how well treatment is working.

Other tests to check for changes to chromosomes and genes

You have several different tests that look for changes:

• on the surface of the leukaemia cells

• in the genes and chromosomes of the leukaemia cells

You have these tests on your blood or bone marrow samples. They are looking for any abnormalities. There are different types of tests. They are called cytogenetic, molecular analysis or polymerase chain reaction (PCR) tests.

Find out more about genetic tests on your CML cells

Immunophenotyping (flow cytometry)

Immunophenotyping are tests to look for certain proteins (​antigens​ ) on the surface of the leukaemia cells.

A specialist laboratory does these tests. Scientists use a technique called flow cytometry to do immunophenotyping. This process uses ​antibodies​  to find cells with certain antigens on their surface.

You have this test on a blood, bone marrow or fluid sample.

This test checks for blast cells in the blood and bone marrow. You might have this test if your doctor thinks you have blast phase of CML. Not everyone has this test as most people with CML at diagnosis have chronic phase.

Find out about the phases of CML

Bone marrow test

A bone marrow test can help to find out more about the type of CML you have. You may also have this test to check whether there are cancer cells in your bone marrow.

There are 2 main types of bone marrow test: 

• bone marrow aspiration

• bone marrow trephine biopsy

Aspiration means your doctor or nurse draws some liquid bone marrow up into a syringe.

A bone marrow trephine biopsy means they remove a very thin 1 or 2 cm long core of bone marrow in one piece.

You usually have both these tests done at the same time. They give some of the same information to the doctor, but there are differences. The bone marrow trephine shows the structure of the bone marrow inside the bone, whereas the aspiration takes just the bone marrow cells. They usually take these samples from the back of your hip bone.

You usually have this test under local anaesthetic. This means that you are awake but the area is numb.

Your haematologist or another doctor called a ​pathologist​ looks at the tissue under a microscope.

Read more about having a bone marrow test

Tests to check for infection

CML and its treatment can weaken your immune system. This is because it stops your bone marrow from making blood cells that help fight infection. This then increases your risk of getting an infection.

You’ll have blood tests to check if you have had or have specific viruses before you start treatment. 

This is to help your doctor understand your risk of developing these viruses during treatment or the risk of them flaring up.

Your doctor usually tests for:

• ​human immunodeficiency virus​ (HIV)

• ​hepatitis B​ virus (HBV)

• hepatitis C virus (HCV)

Chest x-ray

You might have a chest x-ray to check for signs of infection if you have any symptoms.

An x-ray is a test that uses small amounts (doses) of radiation to take pictures of the inside of your body. They are a good way to show changes in organs such as the lungs.

Read more about having an x-ray

Ultrasound scan

You may not need this test if your doctor can feel that your liver or ​spleen​ is larger than it should be.

Ultrasound scans use high frequency sound waves to create a picture of a part of the inside of your body. You might have an ultrasound scan to look for changes in your spleen or liver. 

Find out more about having an ultrasound scan

Tissue typing tests

You have tissue typing tests if your doctor thinks that a ​stem cell transplant​ might be a possible treatment for you. It is to show how closely a possible stem cell donor’s tissue matches your own. 

If you are in accelerated or blast phase CML you might have this test. A stem cell transplant is an uncommon treatment for CML. This is because ​targeted cancer drugs​ work very well at controlling most people's CML.

To tissue type you have one or more of the following tests:

• a blood test

• a swab taken from the inside of your cheek (buccal swab)

• a spit (saliva) sample

Read about having tissue typing tests

Other tests and scans

You might have other tests or scans for CML. We have information about the different tests and scans on our A to Z list.

Go to the tests and scans A to Z list

Treatment for CML

The tests you have help your doctor find out if you have leukaemia and the type of leukaemia you have.

This is important because doctors use this information to recommend the best treatment for you.

Read about the treatment options for CML

Coping with CML

Coping with a diagnosis of CML can be difficult. There is help and support available for you and your family.

Read about what you can do to cope with a diagnosis of CML