What is a bone marrow test?

For some blood disorders, the only way to be certain of what is going on within the bone marrow is to perform a bone marrow test (sometimes referred to as an aspirate or a trephine).  The reason us haematologists are interested in the bone marrow is because this is where the red blood cells, white blood cells and platelets (help you heal if you cut yourself) are made.  When there are problems in the blood tests, it can sometimes be an indication that there is a problem with the production of some or all of these cells within the bone marrow.

What sort of conditions can be diagnosed with a bone marrow test?

The majority of all blood cancers can be diagnosed using  bone marrow test, including acute myeloid leukaemia, chronic myeloid leukaemia, acute lymphoblastic leukaemia, chronic lymphocytic leukaemia, myeloma, myelodysplastic syndrome, myeloproliferative disorders, aplastic anaemia, and a number of rarer problems.  The test is sometimes used to 'stage' a condition, such as lymphoma, once the diagnosis has been made, in order to see how widespread the problem has become.  The bone marrow test can also be useful in diagnosing non-cancerous conditions of the bone marrow.

What is involved in the test?

It is a relatively simple procedure and patients tell me that the thought of the procedure is often worse than the reality.  The procedure is generally performed with local anaesthetic to numb the area over the back of the hips on one side, with the patient lying on the opposite side (see picture).  Depending on the information being sought, the person doing the procedure will use either one or two needles: the first to take some liquid out of the bone marrow ("aspirate") and the second to take a core of the bone ("biopsy").  The tough part of the bone is the outer layer, once through that layer, it is like a honeycomb with gaps for blood cells to be made.  It is therefore not usually very difficult to take samples.


What happens after the test?


The test itself only takes about 5-10 minutes to perform, but afterwards you will be asked to lie on your back for up to 30 minutes to help settle any bleeding that may occur.  Once you have been checked by the nurse, you can leave and go about your daily activities (although the plaster will need to be kept dry for 48 hours).  However, some people take it easy for the rest of the day, and once the local anaesthetic has worn off, it is usually safe to take paracetamol to ease any discomfort that might be felt.


The test results can take anything from a couple of days up to a few weeks to be processed, depending upon which tests are being requested.  Sometimes the diagnosis can be gained on the results that come back early, but sometimes they can't, and the full three week wait is required to get the answer.


What are the potential problems from having the test?


Like a simple blood test, whenever you pass a needle through the skin there is a the potential for bleeding to occur, but this will have stopped before you are allowed to leave the hospital.  Please let your doctor know if you are taking any medicine that make you bleed more, as these sometimes need to be stopped in advance.  Other problems include bruising and infection, although these are uncommon.  If you notice any redness  around the injection site that increases in size, let your doctor know immediately, and antibiotics can be given.  The test can be uncomfortable, but is rarely very painful - but for some people this can occur, and they may require sedation or in extreme cases a full anaesthetic.  Sometimes, despite the test being performed appropriately, insufficient quality samples can be obtained, and that can mean the test needs repeating at a different point in time.

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