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Acute lymphoblastic leukaemia (ALL) tests

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Your healthcare team will order laboratory tests to confirm whether you have acute lymphoblastic leukaemia (ALL), and what type of ALL you have. They start by looking at the bigger picture, and then focus 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. They will need the results of several tests to confirm a diagnosis of ALL.

Full blood count (FBC)

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

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.

Normal blood film

A diagram showing abnormal blood

Abnormal blood film


Bone marrow biopsy

Your doctors will probably want to take a sample of your bone marrow by a procedure called a bone marrow biopsy. 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 which aren’t circulating in your blood yet. Testing your bone marrow is also useful at this point because it can be used to compare your blood cells after treatment to see how well the treatment has worked.

A bone marrow biopsy 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.

Find out more about having a bone marrow biopsy.


People with blood cancer will have changes in the genes of cells affected by the cancer. These changes aren’t the type to be passed on through families. They are only found in the affected cells, such as 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 healthcare team what type of ALL you have (B-cell or T-cell, Philadelphia positive or negative), and therefore what your treatment is likely to be.

Immunophenotyping or flow cytometry

Immunophenotyping, also called flow cytometry, looks at the pattern of proteins on the surface of leukaemia cells. This can confirm a diagnosis of ALL and tell your doctor exactly which type of ALL you have.

Find out more about immunophenotyping.

Other tests

Depending on how well you are after you’re diagnosed, your healthcare team may want to do more tests. These tests aren’t routine and some aren’t necessarily done at diagnosis. Don’t worry if your healthcare team doesn’t suggest you have them.

Lumbar puncture

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. To treat this or prevent it happening, the procedure may also involve anti-cancer drugs (chemotherapy) being introduced to 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 may be injected through the needle. These drugs are safe to give in this way. Your doctor will tell you if you need this treatment.

It’s likely that you won’t have a sedative to make you feel sleepy during a lumbar puncture, as it’s useful for patients to be awake to report any symptoms.

Often, you won’t need a lumbar puncture when you’re first diagnosed, but you’ll generally need several in the course of your treatment.

Blood 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 dosage.

This is a blood test to check how well your kidneys are working. The results will help your doctors work out the doses of drugs you need. It’ll also show if you’re lacking fluids (dehydrated) and show 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 kidneys. 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 the ALL.

Tissue typing is a blood test that’s routinely done when someone’s diagnosed with ALL. It checks your white blood cells for proteins called HLA markers.

If you need a stem cell transplant using cells from another person (a donor) as part of your treatment, this information is used to make sure the donor’s stem cells are a close match to your own, which lowers the risk of problems following the transplant.


You may have an X-ray when you’re first diagnosed, to check for infection or any other chest problems.

This is not a routine test during the diagnosis and treatment of ALL but there may be specific reasons you need a CT or CAT scan, such as if you have a swollen liver or spleen when you are diagnosed.

An MRI scan is not a routine test during diagnosis and treatment of ALL, but there may be specific reasons for having one. For example, it may be done to check if there are signs of ALL in the brain or the fluid around the brain.

It’s rare to have a PET scan to help diagnose ALL, but it may be done if doctors suspect there are leukaemia cells in your lymph nodes (glands), liver or spleen.

An older middle aged Black man in a yellow shirt.

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