Updated 10 Aug 2017

If a healthcare professional thinks you may have CML you’ll have a set of tests to confirm this, then some further tests to determine the right treatment for you.

It’s important that you understand your diagnosis – it might be a good idea to ask your consultant to write it down so you can use it if you’re looking for more information or support, or if you need to tell other people about it.

Signs and symptoms

If you’re diagnosed with CML, there are some symptoms you might notice before your diagnosis. It’s important to remember that not everyone will get all, or even any, of these symptoms. Each person is different, and will have a different experience.

Some people won’t be aware of any symptoms at all and are diagnosed by chance after routine blood tests, or blood tests you were having for something else.

About 90% of people with CML are diagnosed during the chronic phase of the disease and most will be able to stay in this phase for life. This section talks about the symptoms associated with each of the three phases.

Symptoms in the chronic phase

Symptoms in this phase are usually quite vague, and appear and develop very slowly. Remember that many of these symptoms are very common, and are often caused by other things. They include:

  • fatigue, or tiredness – this is sometimes caused by anaemia
  • loss of appetite
  • unexplained weight loss
  • increased sweating, particularly at night
  • abdominal bloating, swelling and occasionally pain (if your spleen is enlarged)
  • blurred vision
  • unusual or excessive bleeding – for example from your gums or nose.

Most patients with chronic phase CML will have an enlarged spleen, which may cause abdominal discomfort (tenderness around the stomach) and a feeling of fullness when you eat. Rarely, the liver might be enlarged at the time of diagnosis.

Symptoms in the accelerated phase

If you’re in the accelerated stage, your symptoms don’t normally change much from the chronic stage. Progression to this stage is measured by looking at changes in your blood, bone marrow and blast count. This stage may sometimes indicate a progression to the more aggressive blast stage. The change in symptoms you might notice from the chronic stage is an increase in bone pain, which may be caused by leukaemia cells building up in your bone marrow.

Symptoms in the blast stage

It’s rare for people to be diagnosed at the blast phase, sometimes known as ‘blast crisis’. It’s also rare, with current treatments, for people to progress from the chronic to blast phase, but both of these things can happen. People in the blast phase often have noticeable extra symptoms. These may include:

  • weight loss
  • fever
  • bone pain
  • tiredness or fatigue
  • bruising more easily than normal
  • unusual bleeding, for example from your gums or nose
  • repeated infections
  • painful haemorrhages
  • swollen lymph nodes
  • blast cells may be present in the fluid which surrounds the brain and spinal cord, and this can cause severe headaches.

Watch Professor Jane Apperley, Consultant Haematologist at Hammersmith Hospital, talk about the symptoms of CML.

Tests and diagnosis

Once a healthcare professional suspects you may have CML, you’ll have a set of tests to confirm whether you have the condition or not. Other people may be diagnosed after a routine blood test. At any time, you can ask your healthcare team to tell you why you’re having a certain test, what the results mean and ask for a copy of the test results.

Tests to diagnose CML

It’s increasingly common for people to be diagnosed with CML by chance, when you have no specific symptoms but are having a routine check up with your GP, or having blood tests for another reason. About 9 in 10 people with CML are diagnosed during the chronic (stable) phase of the disease. The remainder are diagnosed in either the accelerated or blast phase.

Full blood count (FBC)

A full blood count (FBC) measures the number of each type of cell in your blood: red cells, white cells and platelets.

A small sample of blood will be taken from a vein in your arm and checked under a microscope in a laboratory (known as a blood film). You might be sent for this test by your GP as part of a routine check-up. Other people might have one when they’re in hospital for something else.

If you have CML, your FBC will normally show that you have more white blood cells than normal. In particular, you may have increased numbers of some rarer types of white blood cells (basophils and sometimes eosinophils). The number of platelets may be slightly higher too and you might be anaemic.

The way the cells look under the microscope is also distinctive, so all of this information means that your doctors can be reasonably sure about the diagnosis of CML at this point. If this is the case, you’ll need to have more tests to check the extent of the leukaemia.

If you’re diagnosed with CML, you’ll have regular FBCs to monitor your condition.

Polymerase chain reaction (PCR) test

Your doctor will also do a PCR test when you first visit the hospital, using the blood sample taken for your FBC. This will measure the amount of the BCR-ABL1 fusion gene in your blood.

The PCR is an important test that you’ll have throughout your treatment. It’s used to monitor how you’re responding to treatment and to look at whether you might need to change treatments.

Bone marrow aspirate and trephine

Most patients will have a bone marrow sample (biopsy) soon after diagnosis: this will allow your doctors to confirm the diagnosis and provide additional information about the disease.

A small amount of bone marrow is taken from the hip bone using a fine needle (an aspirate). Your doctors will then look at the bone marrow sample under a microscope.

You don’t need to stay overnight in hospital for a bone marrow biopsy; you can have it as an outpatient using local anaesthetic, gas and air, or mild sedation. It’s usually quite quick but may be uncomfortable while the sample is being taken from the marrow; you can take painkillers if you need to after the procedure.

Some patients will also have a bone marrow trephine. This is similar to a bone marrow aspirate, but involves taking a piece of bone from the hip bone instead using a larger needle, under local anaesthetic or mild sedation. The laboratory doctors will do a number of tests on your bone marrow, to look at how many mature and immature cells you have. This helps to confirm the stage of your disease.


Almost everyone with CML will have cytogenetic tests. Cytogenetics is the study of the chromosomes. This test is important as it identifies the Philadelphia (Ph) chromosome and confirms the diagnosis of CML.

Ninety-five percent of patients with CML have a Ph chromosome, which contains the BCR-ABL1 fusion gene. In the remaining 5% of patients a Ph chromosome is not obvious, but the PCR test will identify the BCR-ABL1 gene.

Watch Professor Jane Apperley, Consultant Haematologist at Hammersmith Hospital, talk about the tests used to diagnose CML.


In most forms of cancer, doctors will do tests to ‘stage’ the disease and help to plan treatment. With solid tumours, staging usually refers to how far the cancer has spread from its original site. This isn’t the case for CML, because it’s always in the blood and bone marrow.

When doctors ‘stage’ CML, they are trying to find out what phase the disease is – chronic, accelerated or blast phase – and through this, give your likely prognosis (outlook).

The main difference between the three stages is the number of immature cells or blasts in your bone marrow. When the disease progresses you have more blasts in your bone marrow and more symptoms. If you’re diagnosed with CML, you’ll have some further tests to determine the right treatment for you. This is called staging.

It’s important to know that most people with CML stay in the chronic (or first) phase. If the disease does progress, it doesn’t always do it in a linear manner. So you might move from chronic phase straight to the blast phase. If you do move into the accelerated (second) stage, it doesn’t necessarily mean you’ll progress to the blast phase.

Treatment at the accelerated stage can move you back to the chronic phase. The full blood count (FBC), cytogenetics and the bone marrow aspirate all help doctors stage the disease.

Risk scores

As part of staging, your doctors will look at your risk score. There are three risk scores for CML that you might hear mentioned: Sokal, Hasford and EUTOS. All of these are less important today than before the introduction of TKI, because the great majority of patients respond to these drugs, regardless of their risk score.

Your doctor may use your risk score to help choose the most appropriate drug for you. TKI vary in strength, so it makes sense to use a more potent drug for those at high risk.

These risk scores look at various factors including:

  • your age
  • the size of your spleen
  • the number of blast cells, platelets, basophils and eosinophils in your blood.

Watch Professor Jane Apperley, Consultant Haematologist at Hammersmith Hospital, talk about staging CML.

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