Bone marrow test for hairy cell leukaemia

You have a bone marrow test to check whether there are cancer cells in your bone marrow. Bone marrow is spongy tissue and fluid that is inside your bones. It makes your blood cells. 

You have a bone marrow test to confirm your diagnosis. You may also have this test to check how well your treatment is working. 

A doctor or specialist nurse removes a sample of bone marrow cells or an area of bone marrow in one piece. This is usually from your hip. A specialist doctor can then look at the cells or tissue under a microscope.

Diagram showing a bone marrow biopsy

You usually have the test in the outpatient department of the hospital. 

You're usually awake for the test but you have a local anaesthetic to numb the area. Some people have medicine to make them drowsy (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.

It might be difficult to do the bone marrow aspiration if there is scar tissue (fibrosis) in the bone marrow. The doctors can still do a bone marrow trephine. This is the most useful bone marrow test for diagnosing HCL and assessing how well treatment is working. 

Tests on your bone marrow cells

Your doctor can do different types of tests on your bone marrow sample. These tests help them:

  • find out what type of leukaemia you have
  • check to see if a small number of leukaemia cells are left behind after treatment - this is called minimal residual disease (MRD)

There are different tests to help doctors diagnose leukaemia and look for MRD. These include tests that look for:

  • genetic changes in the leukaemia cells
  • certain proteins (antigens) on the surface of leukaemia cells – this is called immunophenotyping

Genetic tests
There are different ways to look for genetic changes in cancer cells. You might hear these tests called cytogenetic tests, molecular analysis, or FISH (fluorescence in situ hybridisation) tests.  

Doctors are looking for changes in specific genes, for example the:

  • BRAF V600E gene

These genetic tests help your doctor diagnose your type of leukaemia. And understand more about your outlook. They can also help your doctor monitor how well treatment is working.

Testing for proteins (antigens) on the surface of leukaemia cells
This test is called immunophenotyping. Doctors use a technique called flow cytometry to do immunophenotyping. This process uses antibodies to find cells with certain antigens on their surface.  Doctors might do this test on your bone marrow sample.

This helps the doctor find out what type of leukaemia you have. It can also help doctors monitor how well treatment is working and see how your leukaemia is changing.

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

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. If you notice any bleeding apply pressure to the area. If it doesn't stop, contact the hospital.

After the test, your hip might ache for a couple of days. You may need some mild painkillers such as paracetamol to take at home.

If you have a sedative, you need to stay at the hospital for a few hours until it has worn off. And you need someone with you so that you don't have to go home on your own. You can go home that day if you are feeling well enough.

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 scan will be looked at by a specialist doctor and you should get your results within 1 or 2 weeks. You won't get any results at the time of the scan. 

Waiting for test results can make you anxious. Ask your doctor or nurse how long it will take to get them. Contact them if you haven’t heard anything after a couple of weeks.

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.

Contact the doctor that arranged the test if you haven't heard anything after a couple of weeks.

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