Bone marrow test for acute lymphoblastic leukaemia (ALL)

You will almost certainly have a bone marrow test. This is to help find out more information about your acute lymphoblastic leukaemia (ALL). Bone marrow is the spongy tissue and fluid that is inside some of your bones. It makes blood cells.

A doctor or specialist nurse removes a small amount of liquid bone marrow and a very small amount of bone from your hip bone at the back. A specialist doctor looks at the tissue under a microscope and you have a number of genetic tests also done on these samples.  

Diagram showing a bone marrow test

You usually have the test in the outpatient department of the hospital. Or on the ward if you are in in patient. You are awake for the test but you have a local anaesthetic to numb the area.

Some people may have medicine to make them drowsy (sedation Open a glossary item). Some hospitals may use gas and air (Entonox) to help relax you instead of sedation. 

Types of biopsy

There are 2 main types of bone marrow test: 

  • bone marrow aspiration
  • bone marrow trephine biopsy

Aspiration means the doctor or nurse sucks some liquid bone marrow up into a syringe.

A bone marrow trephine means that they remove a very thin 1 or 2cm long core of bone marrow in one piece.

You usually have both of these tests done at the same time. They give some of the same information to the doctor, but there are differences. The bone marrow trephine shows the structure of the bone marrow inside the bone, whereas the aspiration takes just the bone marrow cells.

Preparing for your bone marrow test

Your nurse or doctor will tell you how to prepare for the bone marrow test if you are in hospital. If you are an outpatient your appointment letter will explain what you need to do.

You are usually able to eat and drink beforehand if you aren't having sedation. If you’re having sedation you’ll get specific instructions about when to stop eating and drinking before the test.

Take your medicines as normal unless told otherwise. If you are taking any blood thinning medicines, you might need to stop these before the test. Your doctor will tell you when to stop taking them.

What happens?

Your doctor or nurse gives you information about the procedure and asks you to sign a consent form. This is a good time to ask any questions you have.

You change into a hospital gown and lie on your side with your knees tucked up into your chest. Usually your doctor or nurse takes the sample from the back of your hip bone.

Your doctor or nurse first cleans the area with some antiseptic fluid, which can feel cold. You then have an injection into the skin over the biopsy site to numb the area. They put a thin needle through the skin into the hip bone. This might be uncomfortable but this only lasts a short time. 

Your doctor or nurse sucks a small amount of liquid bone marrow into the needle, using a syringe. You feel a pulling sensation when they start drawing the bone marrow cells out. 

They take the needle out and put in a second one if you're having a trephine biopsy as well. The aim is to get a small amount of marrow out in one piece.

The whole test takes around 30 minutes.

After your bone marrow test

If you have sedation, you need to stay at the hospital for a few hours until it has worn off. And you need someone to take you home and stay with you overnight.

You usually go home the same day if you're feeling well enough.

You have a dressing over the site, which you should keep on for 24 hours. 

Possible risks from bone marrow test

A bone marrow test is very safe and any risks are small. 

During the procedure there is a very small risk of damage to nearby structures, but this is very rare.  


It's not unusual to have a small amount of bleeding from the area where the needle went in. If you notice any heavy bleeding, apply pressure to the area. If it doesn't stop, contact the hospital.


Sometimes blood leaks out of the vein and collects under your skin. This can look like a small dark swelling under the skin (haematoma). Pressing hard once the needle is removed can help


There is a small risk of getting an infection in the wound. Tell your doctor if you have a temperature or if the area becomes red and sore. 


Some people feel uncomfortable and have pain after the local anaesthetic has worn off. Your nurse will tell you what painkillers to take. If you have severe pain or it's getting worse then you should contact the hospital.

Tingling in your leg

You may have some tingling in your leg which wears off with time.

Getting your results

Your bone marrow test will be looked at in the laboratory. The time it takes to receive results depends on which tests are being done on the bone marrow samples. Basic results can be available as soon as 24 to 48 hours. Whereas genetic tests on bone marrow samples can take a couple of weeks. You won't get any results at the time of having the bone marrow taken.  

Waiting for test results can make you anxious. Ask your doctor or nurse how long it will take to get them. If your doctor suspects you have ALL, the tests are processed as an emergency.  

You might have the contact details for a specialist nurse. You can contact them for information and support if you need to. It may help to talk to a close friend or relative about how you feel. 

For support and information, you can call the Cancer Research UK nurses on freephone 0808 800 4040. The lines are open from 9am to 5pm, Monday to Friday

Tests on your leukaemia cells

Other laboratory tests may be carried out on the blood or bone marrow cells you've given. Your haematologist will order these tests to look for changes (abnormalities):

  • on the surface of your leukaemia cells
  • in the genes and chromosomes of your leukaemia cells

These are also sometimes called cytogenetic, molecular analysis or polymerase chain reaction (PCR) tests.


This is an important test to help find out what:

  • type of leukaemia you have such as if you have ALL or another type of leukaemia such as acute myeloid leukaemia (AML)
  • subtype of ALL you have such as B cell or T cell ALL

It can also help find out if your leukaemia has gone away after treatment.

Acute lymphoblastic leukaemia cells look very different on their surface from all other normal cells in the body. These can be easily picked up with another method called flow cytometry. This test helps tell your doctor how well your treatment is working. This test can be carried out on your blood if leukaemia cells are present but it is normally done on bone marrow samples.

FISH (fluorescence in situ hybridisation)

FISH is a test that looks for chromosome changes in cells. It can help your doctor to work out which treatment you need. Philadelphia positive ALL is the main subtype of ALL that is picked up by this method. But there are also many other chromosome changes that are important in helping your doctor understand more about your leukaemia.

Philadelphia chromosome

Some people with ALL have a change in the chromosomes of their leukaemia cells called the Philadelphia chromosome. This is called Philadelphia positive ALL. The name came about as it was first picked up in a laboratory in Philadelphia many years ago. This is when a gene called the ABL1 gene on chromosome 9 breaks off and sticks to a gene called the BCR gene on chromosome 22. It produces a new gene called BCR-ABL1. This gene causes the cell to make too much of a protein called tyrosine kinase. This protein encourages leukaemia cells to grow and multiply.

Watch this 2 minute video to explain what Philadelphia positive leukaemia is. 

Polymerase chain reaction (PCR)

PCR stands for polymerase chain reaction and is a test to pick up changes in genes and chromosomes to help diagnose cancer. It helps your doctor work out the treatment you need. In leukaemia your doctor can also use it to monitor how well your cancer treatment is working.

Other genetic tests:

Newer types of genetic testing are becoming more routine. Doctors are using these to understand more about the gene changes that happen in leukaemia. These tests are done at specialist laboratories that have been set up around the UK. The are called genomic laboratory hubs. 

You can find out more about genomics and these specialist laboratories on the NHS website. 

Tests during treatment

Minimal residual disease (MRD)

You will also have bone marrow tests during treatment. This is to check how well your treatment has worked and help estimate whether your leukaemia is likely to come back. 

A small number of leukaemia cells can be left behind after treatment. This is called minimal residual disease (MRD).

There are two main techniques for finding MRD:

  • molecular test - looking for genetic changes in cells which are specific to your leukaemia 
  • immunophenotyping - looking for certain proteins on the surface of your leukaemia cells
Last reviewed: 
11 Jun 2021
Next review due: 
11 Jun 2024
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  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact with details of the particular issue you are interested in if you need additional references for this information.

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