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 breast bone.
Preparing for a
bone marrow biopsy
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 a bone marrow
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 paracetemol. More powerful
analgesic drugs are rarely required.
What can a bone
marrow biopsy detect?
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
bone marrow biopsy 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.
