To help you understand some of the tests used to diagnose CLL, it can be helpful to know a bit more about cells.
The organs and tissues of our body are made up of cells. Every cell contains all the biological information we inherit from our parents. This information is stored in our genes in the centre (nucleus) of every cell. Genes are grouped together on chromosomes and the genes control what the cell does.
The blood tests you may have include:
- Cytogenetic testing – this looks at the chromosomes in the leukaemia cells. There are often changes in the chromosomes of CLL cells.
- Fluorescent in situ hybridisation (FISH) – this is sometimes used to look for any changes in the leukaemia cells. Knowing what these changes are helps doctors understand how the CLL may behave and plan your treatment.
- Immunophenotyping – this shows which types of white blood cells are abnormal.
- Immunoglobulin testing – this checks the levels of antibodies you have in your blood for fighting infection. CLL cells may also make antibodies that damage your red blood cells.
This uses x-rays to take a picture of your chest, to check your lungs and heart. The x-ray will also look at lymph nodes in your chest.
CT (computerised tomography) scan
This is sometimes done to check how many lymph nodes are affected by CLL and to see whether the spleen is enlarged.
A CT scan takes a series of x-rays, which build up a three-dimensional picture of the inside of the body. The scan takes 10 to 30 minutes and is painless.
It uses a small amount of radiation, which is very unlikely to harm you and will not harm anyone you come into contact with. You will be asked not to eat or drink for at least four hours before the scan.
You may be given a drink or injection of a dye, which allows particular areas to be seen more clearly. This may make you feel hot all over for a few minutes. It’s important to let your doctor know if you are allergic to iodine or have asthma, because you could have a more serious reaction to the injection. You’ll probably be able to go home as soon as the scan is over.
Bone marrow biopsy
Some people may have this test to check how much CLL is in their bone marrow. A small sample (biopsy) of bone marrow is taken from the hip bone. This is usually done under a local anaesthetic in the outpatient department and takes about 10 minutes. It can feel quite uncomfortable but you can take painkillers if you need to.
Insert diagram a small sample of bone marrow being taken from back of hip bone
Lymph node biopsy
This test isn’t usually needed, but some people may have an enlarged lymph node removed so it can be examined under a microscope. You may have this done under a local or general anaesthetic. It’s a small operation and most people can go home on the same day. After the operation, you’ll have a small wound with a few stitches. The stitches are usually taken out after about 7 to 10 days.
CLL can behave very differently in different people. It can often develop slowly over many years – sometimes 20 years or more. However, in some people, CLL develops more quickly.
Cytogenetic tests give information about changes in the chromosomes, such as whether a part is missing or ‘deleted’. This information helps the doctors plan what treatment you are most likely to benefit from. These are the most common changes:
- Between 30–50% of people (3–5 out of 10) with CLL have a cytogenetic change called del (13q). People with this change alone often have a type of CLL that develops extremely slowly and doesn’t need any treatment for many years.
- Less than 10% of people (1 out of 10) have a cytogenetic change called del (17p). This makes the leukaemia more difficult to control. If this is found, a FISH test (fluorescent in situ hybridisation) may be done to see if a gene called TP53 is missing.
- About 40–60% of people (4–6 out of 10) either have other cytogenetic changes in their CLL cells, or none at all. The leukaemia often needs treatment, but usually not immediately. It can be controlled for a number of years with treatment.