A biopsy involves removing a small sample of tissue from on or within the body so that the cells within the tissue can be examined a microscope. Looking for abnormalities or changes in cells can be extremely useful for detecting diseases, particularly cancer.
A bone marrow biopsy analyses cells from within bone to check for blood disorders and other potentially serious health conditions. The results can show if you have a lower than normal number of red blood cells (in which case you might have anaemia), a low white blood cell count (which may mean you are prone to infection) or if you have a low number of platelets (which may prevent your blood from clotting properly).
If any of the blood cells or other components are present in unusually larger quantities in a bone marrow biopsy, this usually indicates a cancer, such as leukaemia, lymphoma or myeloma.
What is bone marrow?
Bone marrow is a jelly-like substance found in the middle of the larger bones. Stem cells within the bone marrow divide and specialise to become red cells, white cells and platelets. Red cells are essential for carrying oxygenated blood from the lungs to the entire body, white cells make up the body’s immune system and platelets are important in the blood clotting process.
How is a bone marrow biopsy carried out?
A bone marrow biopsy can be done in two ways:
Bone marrow aspiration: the liquid component of the bone marrow is removed using a narrow syringe and needle. This type of bone marrow biopsy allows an analysis of the type of cells present and their relative numbers.
Bone marrow trephine biopsy: a solid core of 1-2cm is removed from the bone marrow. This allows analysis of the bone marrow structure and density.
Both tests can be done independently, or they may be performed at the same time.
A bone marrow biopsy takes just a few minutes and is usually performed as an outpatient procedure or as a day case if sedation is needed. The bone marrow biopsy sample is taken from the hip bone, though a bone marrow aspiration can also be taken from your breastbone.
Preparing for the procedure
Bleeding is one of the biggest dangers of a bone marrow biopsy, and so you will be asked to stop or reduce the dose of any anticoagulant medication you take, such as aspirin or warfarin, for a week or so before the procedure. You will usually have a blood test before your bone marrow biopsy to make sure that you do not have any significant problems with blood clotting.
The bone marrow biopsy is done under local anaesthetic, and you may also be given a sedative to help you relax. Despite the anaesthetic, you may still experience a sharp pain for a short time as liquid marrow is extracted, or a dull ache as a solid core is cut.
After the biopsy
Although the bone marrow biopsy is over very quickly, you will need to remain lying down for a short time afterwards so that the clinical staff can check the extraction site for signs of bleeding or other problems. If you have had a sedative, you will be transferred to a recovery room while the effects wear off. You will need to arrange for a friend or family member to escort you home afterwards, as you may not be safe to drive. If you live alone, it is advisable to have someone stay with you for the first 24 hours.
Mild to moderate aching in the area of the extraction site is normal after a bone marrow biopsy and you should find that you feel more comfortable if you take standard painkillers such as paracetamol. More powerful analgesic drugs are rarely required.
What can be detected?
Skilled examination of the bone marrow fluid or core sample can provide evidence for a wide range of diseases. Experienced pathologists will stain and count the number and distribution of cells, and compare these results with the normal range. They will also check for abnormal cells. Bone marrow biopsy results may show one or more of the following:
Problems with red blood cells: the shape and number of red cells present in the bone marrow biopsy sample can show whether someone has a simple anaemia due to iron, vitamin B or folic acid deficiency, or whether they have a more complex condition such as myelofibrosis. This causes the mesh within the bone marrow to become denser, which causes oddly shaped red blood cells.
A low white blood cell count: this can have several causes including a serious infection (such as HIV), blood cancer, an autoimmune disorder that targets bone marrow cells, an inherited disease that leads to poor bone marrow function, or damage to the bone marrow that occurs after chemotherapy.
A low platelet count (thrombocytopenia): this can be the result of thrombocytopenic purpura (ITP and TTP) and haemolytic uraemic syndrome (HUS). HUS has various causes, including food poisoning with E. coli strain 0157:H7.
High numbers of white cells: this can happen if the body has been fighting off a recent and severe infection. This bone marrow biopsy result is possible in someone who has had ‘flu’ for example, or it may be a sign that someone has tuberculosis. White blood cell numbers can increase in many diseases, including autoimmune disorders such as rheumatoid arthritis, and various forms of blood cancer including acute lymphocytic leukaemia (ALL), chronic lymphocytic leukaemia (CLL), acute myelogenous leukaemia (AML), chronic myelogenous leukaemia (CML), and multiple myeloma.
Unusual white cells present: when cancer is affecting another part of the body, some of the cancer cells can start to spread to the bone and can be detected in a bone marrow biopsy. Lymphomas and prostate cancers often spread to bone.
A bone marrow biopsy may also be used to check the progress of a disease see if you are responding to the treatment being given. You may need a bone marrow biopsy at regular intervals to fine tune the dosage, especially where it is important to give as little of the drugs as possible due to side effects.
When will I get my results?
Bone marrow biopsy results normally take between a few days and a couple of weeks to come back, depending on the urgency of the request and the nature of the analysis. Some staining techniques can take a few days and this can delay the results. If your specialist feels that it is important that your results are received quickly, for example if they feel urgent cancer treatment may be needed, this will be accommodated by the labs. Urgent requests such as this will naturally slow down less urgent bone marrow biopsy results. Waiting a little longer may therefore not be a bad thing, even though it can be difficult.