Bone marrow test

This test is to see whether there are cancer cells in your bone marrow. For this test, a doctor or specialist nurse removes a tiny sample of bone marrow cells to look at under the microscope.

Types of cancer it is used for

Bone marrow tests are most often done for cancers that are most likely to affect the bone marrow, such as

• Lymphomas
• Leukaemias
• Myeloma

But it can be done for any type of cancer if your doctor thinks your bone marrow could contain cancer cells, or needs to rule this out for any reason.

There are two main types of bone marrow test – a bone marrow aspiration and a bone marrow trephine biopsy. Aspiration means the doctor or nurse sucks some bone marrow cells up into a syringe. A bone marrow trephine means that they remove a 1 or 2cm core of bone marrow in one piece.

You may 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 biopsy shows the structure of the bone marrow inside the bone, whereas the aspiration takes just the bone marrow cells.

Either test only takes a few minutes and you can have them done as an outpatient. The doctor or nurse usually takes the bone marrow sample from your hip bone. You can have a bone marrow aspiration from your breast bone (sternum) but not a bone marrow biopsy.

First you have a local anaesthetic injection into the skin over the biopsy site – usually your hip bone – to numb it. When this has worked, the doctor or nurse puts the needle in through the skin. It goes into the hip bone or sternum, and into the centre of the bone, where the marrow is. For a bone marrow aspiration, the needle is quite thin. For a bone marrow trephine, the needle is thicker. The needle is attached to a syringe.

If you are having a marrow aspiration, the doctor or nurse then sucks a cubic millilitre of bone marrow cells into the needle. You may feel a pulling sensation when they start drawing the bone marrow cells out. Some people have a sudden, sharp pain. If you are having a trephine biopsy as well, the doctor or nurse will take this needle out and put the second one in.

If you are having a trephine, the doctor or nurse will turn the needle back and forth while pushing it further into the marrow. The aim is to get a 1 or 2 centimetre core of marrow out in one piece. Once it is in far enough, the doctor or nurse draws out the needle, containing its core of marrow. The needle going into the hip bone can be painful, but this only lasts a short time.

Some people prefer to have some type of sedative before the test so that they are a bit drowsy. Sedation of some sort is certainly a good idea for children. If you have a sedative, you will need to stay at the hospital until it has worn off. And you will need someone with you so that you don't have to go home on your own.

After the test, your hip may ache for a couple of days. You may need some mild painkillers to take home or your doctor or nurse may suggest you take some paracetamol.

It can take time for results to come through. Exactly how long may depend on why you are having the test but it may be a couple of weeks.

The bone marrow sample is sent to the medical laboratory as soon as it has been removed. A pathologist examines it under a microscope. To do this, they may need to stain the cells so that the different types show up more clearly. The staining techniques can take a couple of days, depending on what needs to be done. The pathologist's report on the bone marrow sample will be typed up and sent to your specialist.

Understandably, waiting for results can make you very anxious. Try to remember to ask when you can expect the results when your specialist first suggests you have the test. That way, you will know roughly how long they will take. If your doctor needs the test results urgently, they will have written that on the request form. If it isn't an emergency and you haven't heard after a couple of weeks, you can ring your doctor's secretary to check if your results are back.