How chronic myeloid leukaemia is diagnosed

Chronic myeloid leukaemia may sometimes be diagnosed following a blood test for something else. If you have any symptoms that could be due to leukaemia you will usually begin by seeing your GP who will examine you and take a blood test.

If the results of the test are found to be abnormal your GP will refer you to a haematologist at the local hospital for specialist advice and treatment. A haematologist is a doctor who specialises in the treatment of blood problems. In CML the blood test will generally show a high number of immature white blood cells.

At the hospital Back to top

The haematologist at the hospital will take your full medical history before doing a physical examination. You will have a blood test which checks the number and stage of development of all the different types of blood cell.

If the blood test shows that leukaemia cells are present, the doctor will want to take a sample of your bone marrow. This is to confirm the diagnosis so that the best treatment can be planned.

Bone marrow sample/biopsy Back to top

A small sample of bone marrow is taken from the back of the hip bone (pelvis) or occasionally the breast bone (sternum). It is looked at under the microscope by a haematologist to see if it contains any abnormal white blood cells. The haematologist will be able to tell which type of leukaemia it is by identifying the type of abnormal white cell.

The bone marrow sample is normally taken under a local anaesthetic. You are given a small injection to numb the area and a needle is passed through the skin into the bone. A small sample of the bone marrow is then drawn into a syringe for examination under a microscope.

The procedure can be done on the ward or in the outpatients department, and takes about 15–20 minutes. When the marrow is drawn into the syringe it may be painful, but this only lasts a short time. You may be offered a sedative to reduce any pain or discomfort during the test.

Sometimes a small core of marrow will be taken (a trephine biopsy) and this procedure takes a few minutes longer. A special type of needle is passed through the skin to the bone marrow. The needle has a tip that can cut out a sample of the bone marrow. You may feel bruised after the test and have an ache for a few days. This can be eased with mild painkillers.

The samples of bone marrow are examined to find out if the Philadelphia chromosome is present. This information helps the doctors to make decisions about treatment. It can take about a week to get the results of a bone marrow biopsy.

Philadelphia chromosome Back to top

Most people with CML have a genetic abnormality known as a Philadelphia chromosome, which can be detected by laboratory tests.

Every cell in the body has a nucleus that contains chromosomes. Chromosomes are long structures made up of DNA. DNA determines how the cell looks and acts. The Philadelphia chromosome develops when part of chromosome 9 (the ABL gene) wrongly attaches to chromosome 22 (the BCR gene) during cell division. This creates a new gene, known as BCR-ABL which produces a specific new protein. The protein causes the production of an enzyme called tyrosine kinase that stimulates the production of abnormal blood cells by the bone marrow.

The Philadelphia chromosome is not inherited and can't be passed on to your children.