Your doctors will perform laboratory tests to confirm whether you have ALL, and what type you have. Your doctor starts by looking at the big picture, and then narrows in on your exact diagnosis.
Tests to diagnose ALL
It can be hard to understand how doctors know you have leukaemia, when there’s nothing like a lump you can see, as you might get with other cancers. Your doctors diagnose leukaemia by looking at your blood, your bone marrow and your genes. Your doctors will go through the following tests to confirm a diagnosis of ALL:
Full blood count
A full blood count (FBC) measures the number of each type of cell in your blood: red cells, white cells and platelets. Your GP may send you for this test because you’re unwell and they don’t understand why, or you might have one as part of a routine check-up.
You’ll have a blood sample taken, then, in the laboratory, automated machines very accurately count your blood cells. If the count is too high or too low, a small drop of your blood is smeared onto a slide and the doctor or a senior scientist will look at it under the microscope.
If your FBC shows that you may have ALL, you’ll need to go to hospital for more tests. If you’re diagnosed with ALL, you’ll have regular FBCs to monitor your condition during and after treatment.
Bone marrow aspirate and trephine (biopsy)
Your doctors will probably want to take a bone marrow sample. This is the most accurate way of diagnosing the type and level of leukaemia you have. Sometimes it’s not possible to make a diagnosis from a blood sample alone, because there may be leukaemia cells in your bone marrow, but not circulating in your blood yet. A bone marrow test is also useful at this point because it can be used to compare your blood cells after treatment to see how well you’ve responded.
Here’s what happens: you’ll lie on your side and a small needle will be used to give some local anaesthetic (only numbing a specific area of the body) into the skin around the back of your hip bone. Using an aspirate (a larger needle which is inserted into the bone), a small amount of bone marrow is taken from your hip bone; this procedure is called a bone marrow aspirate. A piece of bone may also be taken using a different needle, and this is called a trephine.
Taking the sample is usually quite quick, but it may feel painful while it’s being done. For this reason, patients are usually offered sedation if they want it. This may be using gas and air (more familiarly used during childbirth) or with an injection into the veins.
You’ll be advised not to take ibuprofen-based painkillers during this time, as they can cause bleeding which can be especially dangerous if you have a low platelet count.
Your doctors will then look at your bone marrow sample under a microscope.
This test gives your doctors more information about:
- the structure of your bone marrow
- the types of blood cell in your bone marrow
- the number of blood cells in your bone marrow (too many or too few).
The results can also tell them if the blood cells in your bone marrow are cancerous.
Every kind of cancer, including blood cancer, changes the genes of the affected cells. These gene faults are not the same thing as genes passed through families (the fault is only in your leukaemia cells).
The study of these gene changes is called cytogenetics or molecular genetics. Cytogenetic tests are usually done on cells from your blood or from your bone marrow, before you start any treatment.
Information about these gene changes is very important. It’s these cytogenetic tests that will tell your doctors what subtype of ALL (B cell, T cell or Philadelphia positive) you have, and therefore what your treatment is likely to be.
Flow cytometry (immunophenotyping)
Flow cytometry, or immunophenotype analysis, looks at the pattern of proteins on the surface of your leukaemia cells. Samples from your bone marrow or blood cells are combined with a particular type of antibody (a protein made by your white blood cells to fight infection), which will stick to the surface of a leukaemia cell, but not to a normal cell.
As the cells pass through a machine, the results are plotted on a graph, showing how many leukaemia cells are present, and what type they are. This test can confirm a diagnosis of ALL, and tell your doctor exactly which type of ALL you have.
Depending on how well you are after you’re diagnosed, your doctors may want to do additional tests. These tests aren’t routine and some aren’t necessarily done at diagnosis, so don’t worry if your doctors don’t suggest you have them.
Leukaemia cells can get into the fluid that cushions your brain and spinal cord. This fluid is called the cerebrospinal fluid, or CSF. A lumbar puncture is a test to see if there are leukaemia cells in your CSF. The doctor inserts a thin needle into your spine, to collect a sample of the fluid. You’ll have a local anaesthetic to numb the area first. After fluid has been collected, drugs used to treat ALL will be injected through the needle (which is safe to give in this way).
It’s likely that you won’t have sedation during lumbar punctures, as it’s useful for patients to be awake to report any symptoms.
Often, you won’t need a lumbar puncture when first diagnosed, but you’ll generally need several during the course of your treatment.
X-rays provide very good images of the denser tissues in the body, such as bone. Your doctors may use an X-ray when you’re first diagnosed, to check for infection or any other chest problems.
A CT (computed tomography) scan is a type of X-ray. You’ll lie on a table that moves into a cylindrical tunnel while the pictures are taken. You may need to have a dye injected into one of your veins, to help get a better image. This is not a routine test during the diagnosis and treatment of ALL but there may be specific reasons it needs to be done, such as if you have a swollen liver or spleen at diagnosis.
Another type of scan is an MRI (magnetic resonance imaging). This scan shows up soft tissues (non-bony parts) and uses radio waves rather than X-rays. You’ll be asked to lie on a table, which will move you through the scanner. You may need to have an injection of some dye. An MRI is not a routine test done during diagnosis and treatment of ALL, but there may be specific reasons it needs to be done.
A PET (positron emission tomography) scan is similar to an MRI, but you’re injected with a radioactive sugar. The levels of radiation used are very small and won’t harm you or anyone nearby. Again, this test is not necessarily routinely done at diagnosis, but it may be done if you have swollen lymph nodes, and doctors want to diagnose. It may also be done to compare your results after treatment.
Liver function tests
This is a blood test to check if your liver is working normally. It’s very important if you need chemotherapy, as many drugs are broken down in the liver. If your liver isn’t working normally, it might be necessary to adjust your doses.
Urea and electrolytes
This is a blood test to check how well your kidneys are working. The results will help your doctors calculate the doses of drugs you need. It’ll also show if you’re dehydrated, and any damage that may have been caused either by the cancer or your treatment. You’ll usually have your kidneys checked every time you have an appointment at the hospital.
When you’re diagnosed with ALL, you’ll also have a general health check-up. This will help work out if you’ll be particularly vulnerable to side effects from treatment. You’ll have a range of tests to check your heart, liver and kidney function. It’s also routine to be tested for HIV, hepatitis B and hepatitis C, so that if you have these conditions without knowing, they can be treated at the same time as your ALL treatment.
> Find more information on tests from a website supported by the Department of Health