Bone Marrow Aspiration & Biopsy

Bone marrow aspiration and biopsy is a diagnostic procedure in which a doctor collects a small sample of the soft, spongy tissue inside your bones to examine it under a microscope.

Bone marrow is the factory inside your bones where blood cells are made. By looking at a sample of this tissue, doctors can see whether blood cells are being produced in the right numbers, the right shapes, and the right way. Two samples are taken in the same session: an aspiration (a liquid sample of the marrow cells, drawn out with a needle) and a biopsy (a tiny solid core of bone and marrow, removed with a slightly wider needle). Together, these two samples give the laboratory a complete picture that cannot be obtained from a blood test alone.

Doctors request this procedure when blood test results are abnormal and they need to understand what is happening inside the bone marrow itself. It is used both to make a first diagnosis and to monitor how a known blood condition is responding to treatment.

• Leukaemia (blood cancer that starts in the marrow)
• Lymphoma (cancer of the lymphatic system) that may have spread to the marrow
• Multiple myeloma (a cancer of plasma cells, a type of white blood cell, that lives in the marrow)
• Anaemia (low red blood cell count) that cannot be explained by blood tests alone, including aplastic anaemia (a condition where the marrow stops making enough blood cells)
• Myelodysplastic syndromes (conditions where the marrow makes abnormal or too few blood cells)
• Myeloproliferative disorders (conditions where the marrow makes too many blood cells)
• Unexplained thrombocytopenia (a low platelet count) or thrombocytosis (a very high platelet count)
• Unexplained enlargement of the spleen or liver when a blood disease is suspected
• Staging — checking how far a cancer has spread — in certain lymphomas and other cancers
• Monitoring the marrow after a bone marrow or stem cell transplant

There are some situations where the procedure may need to be postponed or handled with extra care.

• Patients taking blood thinners may need their medication adjusted before the procedure to reduce bleeding risk
• Active skin infection or open wound at the planned needle site — the doctor will choose a different location or wait until the infection clears
• Severe, uncorrected bleeding disorders may require special preparation first

Because this is a diagnostic procedure using a needle on a small, controlled area, it is generally considered low-risk; however, as with any procedure that enters the body, some complications can occur.

• Pain or tenderness at the needle site lasting a few days — the most common experience
• Bruising or mild bleeding around the puncture site
• Infection at the site, which is uncommon because the area is carefully cleaned and sterile equipment is used
• Prolonged bleeding, more likely in patients who have low platelet counts or are on blood thinners
• Rarely, injury to surrounding structures — the site chosen (usually the back of the hip bone) is selected precisely because important nerves and organs are not nearby
• In very rare cases, a small fragment of bone may require additional attention if the biopsy core does not come out cleanly

Preparation for bone marrow aspiration and biopsy is straightforward. In most hospitals, the procedure does not require general anaesthesia (being put fully to sleep), so fasting rules are usually more relaxed than for surgery. Your care team will give you specific instructions, but the following gives you a general idea of what to expect.

Before the procedure, your doctor will typically review any blood thinners or anti-inflammatory medicines you take, as some of these may need to be paused for a period of time. You do not normally need to fast unless your care team asks you to — ask them directly if you are unsure. Smoking and alcohol are generally best avoided in the days beforehand as they can affect healing.

Blood tests that are usually ordered beforehand include a full blood count (a complete picture of how many of each type of blood cell you have), a coagulation screen (tests that check how well your blood clots), and sometimes a blood-type test. Imaging such as an X-ray of the hip area is occasionally done if there is a reason to check the bone first.

The procedure itself typically follows these steps:

• You are positioned lying on your stomach or on your side, depending on the site chosen — most commonly the posterior iliac crest (the back of the hip bone)
• The skin over the site is cleaned thoroughly with an antiseptic (a germ-killing solution)
• A local anaesthetic (numbing medicine injected under the skin) is given to reduce pain; you may feel a short sting and then pressure but usually not sharp pain
• For the aspiration, a hollow needle is pushed through the skin and into the bone; liquid marrow is then drawn up into a syringe — you may feel a brief, sudden pulling sensation at this moment
• For the biopsy, a slightly wider needle is rotated into the bone to collect a small solid core of marrow tissue, about the size of a grain of rice
• Both needles are removed, and firm pressure is applied to stop any bleeding
• A dressing (bandage) is placed over the site
• The samples are labelled and sent to the laboratory; the whole procedure from first needle to dressing usually takes around fifteen to thirty minutes, though this varies

Most patients are observed for a short period after the procedure — usually in a recovery area — to make sure there is no significant bleeding from the site. Because local anaesthesia is used rather than general anaesthesia, most people feel well enough to go home the same day, though your care team will confirm this. Some soreness at the biopsy site is normal and usually settles within a few days.

• Keep the dressing clean and dry for the first day or two; your nurse will advise when it is safe to shower or bathe
• Avoid strenuous activity, heavy lifting, and swimming until the site has healed — your doctor will advise on the timeframe based on how you are healing
• Over-the-counter pain relief (such as paracetamol) is usually enough for the soreness; your care team will advise what is safe given your specific blood condition — avoid anti-inflammatory pain medicines unless your doctor approves, as these can affect bleeding
• Watch the site for signs of infection: increasing redness, swelling, warmth, discharge, or a fever — contact your care team if any of these develop
• Results from the laboratory take days to weeks depending on the tests ordered; your doctor will schedule a follow-up appointment to discuss the findings
• If you are having the procedure to monitor a known condition or after a transplant, your care team will explain the follow-up schedule that applies to your specific situation
• Resume blood thinners or other paused medicines only when your doctor confirms it is safe to do so