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What is bone marrow?

Bone marrow is a spongy material found inside some large bones of the body. It is where stem cells are formed. Stem cells are blood cells at a very early stage of development. They can divide and develop into any of the three main types of blood cells:  

  • red blood cells, which carry oxygen to all cells in the body 
  • white blood cells, which help to fight infection  
  • platelets, which help blood to clot. 

What is a bone marrow biopsy?

A bone marrow biopsy involves taking a trephine and/or an aspirate sample from the bone marrow.  

  • A trephine sample is when we remove a small core of bone marrow.  
  • An aspiration removes a sample of the bone marrow fluid. 

Both samples can be examined with a microscope or tested in other ways to identify abnormal cells. 

Why do I need a bone marrow biopsy?

Your doctor has recommended that you should have the biopsy to investigate a problem with your blood cells. This could be the red or white blood cells, or the platelets. 

You may also need to have the bone marrow biopsy:  

  • to monitor how you respond to your treatment, or  
  • to see if a disease is progressing.

A bone marrow biopsy gives the most accurate information about your diagnosis. 

What are the risks of having a bone marrow biopsy?

Bone marrow biopsy is a simple and safe procedure. But as with any procedure, there are some risks of having it. 

Pain: Most people feel pain or discomfort at times. We will aim to keep this to a minimum but please tell the person doing the biopsy if you cannot tolerate this.  

Bleeding: There should be very little bleeding or none at all at the biopsy site. Your doctor or nurse will check this before you leave. If you are concerned about bleeding once you have left the hospital, please contact us

Bruising: You may have some bruising or feel some discomfort around the biopsy site after the procedure. This is usually temporary, and you can take some over-the-counter pain relief if needed. 

Infection: If you notice any of the symptoms listed below, contact us as soon as possible: 

  • swelling at the biopsy site 
  • discharge 
  • tenderness 
  • throbbing 
  • raised temperature (over 38° C). 

This is because you may have an infection and need a course of antibiotics to treat it. 

Are there any alternatives?

There isn’t an alternative to a bone marrow biopsy at present. If you choose not to have the biopsy, your doctor will talk to you about the options available to you. 

How do I prepare for the biopsy?

  • If you take medicines that thin the blood (anti-coagulants), you may need to stop them before the biopsy. Your clinical nurse specialist (CNS) will tell advise you. If you haven’t stopped taking them despite your CNS advising you to, we may have to reschedule your appointment. 
  • You can eat and drink as normal.  
  • Please wear loose and comfortable clothing. 

Asking for your consent

We want to involve you in all the decisions about your care and treatment. If you decide to go ahead with having the biopsy, we will ask you to sign a consent form. This confirms that you agree to have the procedure and understand what it involves. We will explain all the risks, benefits and alternatives before you sign the consent form. If you are unsure about anything, please ask us. 

What happens during the bone marrow biopsy?

Your bone marrow biopsy will take place in the Supportive Care Unit. Please arrive 15 minutes before your appointment. 

Bone marrow samples are usually taken from the pelvis bone. You can feel this bone just below each side of your waist. 

There are two ways of obtaining a sample: 

  • either using hand-operated equipment 
  • or using a mechanical device. 

The doctor or nurse performing the biopsy will ask you to lie on your side with your knees bent up to your chest. They will clean the skin over the biopsy site with antiseptics. 

You will then have an injection of local anaesthetic into the tissue around the bone. This will make the procedure more comfortable for you. The injection may sting a little but should wear off after a few minutes as the area becomes numb. 

For the aspirate sample: Your doctor or nurse will pass a hollow needle through the skin into the bone. The needle will have a syringe attached to it. As the liquid is being withdrawn from the bone marrow, you may have a brief, sharp pain in your bone, buttock and leg.

For the trephine sample: Your doctor or nurse will insert a hollow needle into the bone and collect a small section of the bone marrow. This may cause some discomfort and you may feel some pressure. Please tell your nurse or doctor if it’s too painful. Once the sample has been collected, the needle will be removed and a dry dressing applied. 

The bone marrow biopsy takes about 20 to 30 minutes to complete. 

What happens after the biopsy?

  • You will need to lie on your back for 10 minutes so that we can monitor you for any bleeding. 
  • You may have some discomfort and bruising over the biopsy site for about 24 hours. You can take your usual painkillers to ease this. If the pain persists after 24 hours, contact us
  • The doctor or nurse will tell you when you can expect to have the results. 
  • You will need to keep the dressing in place until the following day. It’s also important that you keep the dressing dry. 
  • If you notice any signs of infection, contact us
  • If you have not had a recent blood test you will need to have one after your biopsy. One of the nurses will advise you where to go. 

Contact us

Supportive Care Unit

Haematology/Oncology Daycare, 4th floor, University College Hospital Macmillan Cancer Centre, Huntley Street, London WC1E 6AG 

Telephone: 020 3447 1808 (8am to 8pm, Monday to Friday) 

Out-of-hours advice: 07852 220 900 

Page last updated: 02 July 2024

Review due: 01 June 2026