Bone Marrow Biopsy: What to Expect, Procedure & Results

What Is a Bone Marrow Biopsy?

A bone marrow biopsy is a diagnostic procedure that involves extracting a small sample of bone marrow tissue from inside a bone, typically the hip bone. The sample is examined under a microscope to assess the health and function of blood cell production and to diagnose various blood disorders and cancers.

Bone marrow is the soft, spongy tissue found inside the central cavity of certain bones, including the hip bones, sternum (breastbone), and vertebrae. This remarkable tissue serves as the body's blood cell factory, continuously producing red blood cells (which carry oxygen), white blood cells (which fight infection), and platelets (which help blood clot). Every day, your bone marrow produces billions of new blood cells to replace those that die naturally or are lost through bleeding.

When doctors suspect a problem with blood cell production or need to investigate unexplained blood test abnormalities, they may recommend a bone marrow biopsy. This procedure provides detailed information about the cellular composition, structure, and function of the bone marrow that cannot be obtained through blood tests alone. The extracted sample allows pathologists and hematologists to examine the types and proportions of cells present, identify abnormal cells, and assess whether the marrow is producing blood cells normally.

A bone marrow examination typically includes two complementary techniques: bone marrow aspiration and bone marrow biopsy (also called trephine biopsy). In aspiration, a needle withdraws liquid marrow containing cells and plasma. In biopsy, a slightly larger needle extracts a small core of solid bone marrow tissue. Together, these samples provide comprehensive information about marrow structure and cellular activity. Most procedures perform both tests simultaneously to maximize diagnostic information.

Anatomy of Bone Marrow

Understanding the anatomy of bone marrow helps explain why this procedure is so valuable for diagnosis. The bone marrow consists of two main types of tissue. Red marrow is actively involved in blood cell production (hematopoiesis) and contains stem cells that develop into red blood cells, white blood cells, and platelets. Yellow marrow consists primarily of fat cells and serves as an energy reserve. In adults, red marrow is found mainly in flat bones like the pelvis, sternum, skull, and vertebrae, while long bones like the femur contain mostly yellow marrow.

The posterior iliac crest of the hip bone is the preferred site for bone marrow biopsy because it contains abundant red marrow, is easily accessible, and is relatively far from vital structures. The bone at this location is also thick enough to accommodate the biopsy needle safely. In some cases, particularly in infants or when the hip cannot be used, the sternum or tibia may serve as alternative biopsy sites.

Why Is a Bone Marrow Biopsy Performed?

Doctors order bone marrow biopsies to diagnose blood cancers like leukemia and lymphoma, investigate unexplained anemia or abnormal blood counts, stage certain cancers, evaluate treatment response, and assess bone marrow function before stem cell transplantation.

A bone marrow biopsy serves multiple important diagnostic and monitoring purposes in medicine. Your doctor may recommend this procedure for various reasons, depending on your symptoms, blood test results, and medical history. Understanding why this test is necessary can help alleviate anxiety and ensure you're prepared for the procedure.

One of the most common reasons for bone marrow biopsy is to diagnose blood cancers and related disorders. Leukemia, lymphoma, and multiple myeloma all affect the bone marrow directly or may spread to it. The biopsy allows doctors to identify cancer cells, determine the specific type of cancer, and assess how extensively the disease has affected normal marrow function. This information is essential for choosing the most effective treatment approach and predicting prognosis.

Doctors also use bone marrow biopsy to investigate unexplained blood count abnormalities. If routine blood tests reveal unusually low red blood cells (anemia), low white blood cells (leukopenia), low platelets (thrombocytopenia), or elevated counts of any cell type, examining the marrow can reveal whether the problem stems from inadequate production, destruction, or abnormal cell development. Conditions such as aplastic anemia, myelodysplastic syndromes, and myeloproliferative disorders can only be definitively diagnosed through bone marrow examination.

Beyond diagnosis, bone marrow biopsy plays a crucial role in cancer staging. For certain cancers that originate elsewhere in the body, determining whether the disease has spread to the bone marrow helps doctors understand the extent of the cancer and plan appropriate treatment. This staging information influences decisions about chemotherapy intensity, radiation therapy, and other treatments.

Monitoring treatment response is another important application. After chemotherapy or other treatments for blood cancers, repeat bone marrow biopsies can show whether cancer cells have been eliminated, reduced, or remain unchanged. This information guides decisions about continuing, changing, or stopping treatment. Similarly, before bone marrow or stem cell transplantation, biopsies verify that the marrow is suitable for the procedure.

How Should I Prepare for a Bone Marrow Biopsy?

Adults typically need no special preparation for bone marrow biopsy. You can eat and drink normally before the procedure. However, you should inform your doctor about all medications you take, especially blood thinners, and discuss any allergies to local anesthetics or sedatives.

Preparing for a bone marrow biopsy is generally straightforward for adult patients. Unlike many medical procedures, there are usually no fasting requirements or extensive preparations needed. However, taking certain steps before your appointment can help ensure the procedure goes smoothly and you feel as comfortable as possible.

Before your scheduled biopsy, your doctor will review your current medications with you. Blood-thinning medications such as warfarin, aspirin, clopidogrel, or direct oral anticoagulants may need to be temporarily stopped before the procedure to reduce bleeding risk. Never stop any medication without specific instructions from your doctor, as some conditions require continuous anticoagulation. Your doctor will weigh the bleeding risk against the risk of stopping the medication and provide personalized guidance.

It's important to inform your healthcare team about any allergies you have, particularly to local anesthetics (like lidocaine), sedatives, or latex. If you've had adverse reactions to anesthesia in the past, share this information so appropriate alternatives can be arranged. Additionally, let your doctor know if you have any bleeding disorders or have experienced excessive bleeding with previous procedures or dental work.

Preparation for Children

The preparation process is quite different for children. Because children may not be able to remain still during the procedure, bone marrow biopsies in pediatric patients are typically performed under general anesthesia. This requires specific preparations that your child's medical team will explain in detail.

Children usually need to fast for six hours before the procedure if general anesthesia will be used. This means no food or drinks during this period. Clear fluids may be permitted up to a certain time before anesthesia, but follow your medical team's specific instructions carefully. The fasting requirement prevents complications during anesthesia, as food or liquid in the stomach could be aspirated (breathed into the lungs) during sedation.

Preparing a child emotionally for the procedure is also important. Depending on the child's age, you might explain the procedure in simple, age-appropriate terms. Many hospitals have child life specialists who can help prepare children through play therapy, visual aids, or tours of the procedure area. Bringing a favorite toy or comfort item can help reduce anxiety.

What Happens During a Bone Marrow Biopsy?

During a bone marrow biopsy, you lie on your stomach or side while the doctor cleans the skin over your hip bone, injects local anesthetic, and uses a special needle to extract a small sample of liquid bone marrow (aspiration) and sometimes a core of solid tissue (biopsy). The procedure takes about 10-15 minutes.

Understanding what happens during a bone marrow biopsy can help reduce anxiety and prepare you for the experience. The procedure follows a systematic approach designed to maximize patient comfort while obtaining diagnostic samples. Here is a detailed description of what you can expect from start to finish.

When you arrive for your procedure, a nurse or medical assistant will review your medical history, confirm your identity and the planned procedure, and check your vital signs (blood pressure, heart rate, temperature). You'll have an opportunity to ask any final questions and sign consent forms if you haven't already. If you're feeling anxious, let your healthcare team know, as they may offer a mild sedative to help you relax.

The procedure typically takes place in a treatment room, clinic, or hospital procedure area. You'll be asked to change into a hospital gown and lie on an examination table. Most commonly, you'll lie on your stomach (prone position) or on your side with your knees drawn up toward your chest. The position exposes the back of your hip, where the posterior iliac crest provides the best access to bone marrow. A pillow may be placed under your abdomen for comfort.

Step-by-Step Procedure

Step 1: Skin preparation. The doctor or nurse will clean the skin over your hip bone with an antiseptic solution (usually chlorhexidine or povidone-iodine). This removes bacteria from the skin surface and reduces the risk of infection. A sterile drape is placed around the area, leaving only the biopsy site exposed. The medical team will be wearing sterile gloves throughout the procedure.

Step 2: Local anesthesia. The doctor injects local anesthetic (typically lidocaine) into the skin first, which feels like a brief sting or burn. Then, using a longer needle, anesthetic is injected deeper into the tissue and periosteum (the membrane covering the bone). This is often the most uncomfortable part of the procedure, as the periosteum is quite sensitive. After a few minutes, the area becomes numb, though you may still feel pressure sensations.

Step 3: Bone marrow aspiration. Once the area is thoroughly numbed, the doctor inserts a hollow aspiration needle through the skin and into the hip bone. You'll feel firm pressure as the needle advances. The needle penetrates approximately half a centimeter into the bone to reach the marrow cavity. Using a syringe attached to the needle, the doctor withdraws a small amount (usually 1-5 mL) of liquid bone marrow. Many patients describe feeling a brief, sharp pulling or cramping sensation during aspiration, as the negative pressure draws marrow cells into the syringe. This sensation typically lasts only a few seconds.

Step 4: Trephine biopsy (if performed). For many diagnostic situations, the doctor also obtains a solid core of bone marrow tissue using a slightly larger trephine needle. This needle is rotated as it advances to cut out a small cylinder (about 1-2 cm long) of bone and marrow. When the needle is removed, the tissue sample comes with it. You may feel pressure and a twisting sensation during this step. The solid sample provides information about marrow architecture that cannot be obtained from liquid aspiration alone.

Step 5: Completion and bandaging. After collecting the necessary samples, the doctor removes the needle and applies firm pressure to the biopsy site for several minutes to stop any bleeding. A bandage is then placed over the site. You'll be asked to lie on your back for 10-15 minutes, applying pressure with your body weight to the biopsy site. This helps minimize bleeding and bruising.

What Does It Feel Like?

While everyone's experience differs, most patients describe the procedure as uncomfortable but tolerable rather than severely painful. The local anesthesia effectively numbs the skin and superficial tissue, so you shouldn't feel sharp pain from the needle puncture. However, you will likely feel:

• Pressure when the needle advances through soft tissue and into the bone
• A brief stinging sensation during local anesthetic injection
• A pulling or cramping feeling during aspiration (lasting only seconds)
• A sense of pressure and rotation during trephine biopsy

If you experience significant pain during the procedure, tell your doctor immediately. Additional local anesthetic can be administered if needed. Some patients find it helpful to take slow, deep breaths during the more uncomfortable moments. Sedation is available for patients who are very anxious or have had difficulty tolerating the procedure in the past.

What Should I Expect After a Bone Marrow Biopsy?

After a bone marrow biopsy, you'll have a bandage over the site that should stay on until evening. Expect some soreness and bruising for several days. Most people resume normal activities the same day, though strenuous exercise should be avoided for 24-48 hours. Contact your doctor if you experience heavy bleeding, fever, or increasing pain.

The recovery period after a bone marrow biopsy is generally brief and uncomplicated. Understanding what to expect in the hours and days following the procedure helps you care for the biopsy site properly and recognize any signs that might require medical attention.

Immediately after the procedure, you'll rest for about 15-30 minutes while the medical team monitors you for any immediate complications. Your vital signs will be checked, and you'll receive aftercare instructions. If you received sedation, you'll need to wait until its effects wear off sufficiently before leaving. Someone should drive you home if you received any sedative medication.

The bandage applied after the procedure should remain in place until evening on the day of your biopsy. After that, you may remove it and shower or bathe normally if you wish. Some doctors recommend keeping the site dry for 24 hours. There's no need for special wound care, though keeping the area clean is important. A small adhesive bandage can be applied if the site continues to ooze slightly.

Common After-Effects

It's normal to experience certain effects in the days following your biopsy. Being aware of these helps distinguish expected recovery from potential complications:

• Soreness at the biopsy site: Most people experience tenderness and discomfort at the hip for several days to a week. Over-the-counter pain relievers like acetaminophen can help. Avoid aspirin and anti-inflammatory medications (like ibuprofen) for the first 24 hours unless your doctor approves, as these can increase bleeding.
• Bruising: A bruise (blue or purple discoloration) commonly develops around the biopsy site and may spread over several days before gradually fading. This is normal and doesn't indicate a problem.
• Mild bleeding: Some oozing from the puncture site is normal in the first day. If bleeding soaks through the bandage, apply firm pressure for 10 minutes.

Most people can resume normal activities on the same day as the procedure or the following day. However, you should avoid strenuous physical activity, heavy lifting, and intense exercise for 24-48 hours to minimize the risk of bleeding or discomfort at the biopsy site. You can return to work, school, or other routine activities as soon as you feel comfortable doing so.

What Do Bone Marrow Biopsy Results Mean?

Bone marrow biopsy results describe the cellularity (how many cells are present), the types and proportions of cells, any abnormal cells, and genetic or molecular findings. Results are typically available within a few weeks and are interpreted by a hematopathologist in conjunction with your clinical symptoms and other test results.

The samples obtained during your bone marrow biopsy undergo extensive laboratory analysis. Understanding what the results mean helps you have informed discussions with your doctor about your diagnosis and treatment options. Results are typically ready within one to three weeks, depending on the specific tests performed.

A specialist doctor called a hematopathologist examines the bone marrow samples under a microscope and performs or oversees various laboratory tests. The analysis evaluates multiple aspects of marrow structure and function, generating a detailed report that your treating physician will interpret in the context of your overall clinical picture.

Components of Bone Marrow Analysis

Cellularity refers to the proportion of the marrow space occupied by blood-forming cells versus fat. Normal cellularity varies with age, roughly following the formula: cellularity (%) = 100 minus age. For a 30-year-old, approximately 70% cellularity is normal; for a 70-year-old, approximately 30%. Hypercellular marrow (more cells than expected) may indicate leukemia or myeloproliferative disorders. Hypocellular marrow (fewer cells) may suggest aplastic anemia or bone marrow failure.

Cell lineage assessment examines the three main blood cell lines: erythroid (red blood cell precursors), myeloid (white blood cell precursors), and megakaryocytic (platelet precursors). The pathologist evaluates whether cells are maturing normally through their developmental stages, whether proportions between lineages are appropriate, and whether any abnormal cells are present.

Morphology describes the appearance of individual cells. Abnormal cell shapes, sizes, or features can indicate specific disorders. For example, certain types of immature cells called "blasts" may indicate leukemia, while abnormally shaped red cell precursors might suggest myelodysplastic syndrome.

Special stains and tests provide additional diagnostic information. Iron staining reveals iron stores and how iron is being utilized for red blood cell production. Immunohistochemistry uses antibodies to identify specific proteins on cell surfaces, helping classify cell types. Flow cytometry analyzes cell surface markers on thousands of individual cells, essential for diagnosing and classifying leukemias and lymphomas.

Cytogenetic and molecular studies examine the chromosomes and genes within marrow cells. Chromosomal abnormalities (such as translocations, deletions, or extra chromosomes) provide crucial diagnostic and prognostic information for many blood cancers. Molecular tests can detect specific gene mutations associated with certain diseases, which may influence treatment decisions.

What Are the Risks and Complications?

Bone marrow biopsy is a very safe procedure with a complication rate of less than 1%. The most common issues are temporary pain, bleeding, and bruising at the biopsy site. Serious complications such as infection or significant bleeding are rare, especially when the procedure is performed by experienced practitioners.

Like any medical procedure that penetrates the skin, bone marrow biopsy carries some risks. However, it's important to understand that this is considered a very safe procedure with an excellent safety profile when performed by trained medical professionals. Serious complications are rare, occurring in well under 1% of procedures.

The most common side effects are minor and temporary. Pain and discomfort at the biopsy site affect most patients to some degree and typically resolve within a few days to a week. Bruising is also common and may take one to two weeks to fade completely. Minor bleeding at the puncture site usually stops with pressure and doesn't require treatment.

More significant complications, while rare, can include:

• Excessive bleeding: Patients with low platelet counts or bleeding disorders have higher risk. Your doctor may order blood tests before the procedure to assess bleeding risk and may give platelet transfusions if needed.
• Infection: Proper sterile technique minimizes this risk. Signs of infection include increasing redness, warmth, swelling, fever, or pus at the biopsy site.
• Persistent pain: Rarely, some patients experience prolonged discomfort that may require additional pain management.
• Needle breakage: Very rarely, a needle may break during the procedure, requiring minor surgery to remove the fragment.
• Damage to nearby structures: The posterior iliac crest is specifically chosen because it's far from major blood vessels and nerves, making injury to these structures extremely unlikely.

Certain conditions may increase the risk of complications. Patients with very low platelet counts, those taking blood thinners, people with bleeding disorders, and those with compromised immune systems may require special precautions. Your doctor will assess your individual risk factors and take appropriate measures to minimize complications.

Bone Marrow Biopsy in Children

Children usually undergo bone marrow biopsy under general anesthesia to ensure they remain still and comfortable. The procedure takes about 30 minutes including sedation time. Children need to fast for 6 hours before anesthesia. Recovery is typically quick, with most children resuming normal activities within 24 hours.

When children require bone marrow examination, the approach differs significantly from adult procedures. The primary difference is that children typically receive general anesthesia rather than just local anesthesia. This ensures the child remains completely still during the procedure, which is essential for safety and obtaining adequate samples. Anesthesia also eliminates any pain or awareness of the procedure, reducing psychological trauma.

The decision to use general anesthesia takes into account several factors unique to pediatric patients. Young children cannot be expected to understand why they must hold perfectly still while experiencing an uncomfortable procedure. Even cooperative older children may have involuntary movements or become distressed during the procedure. General anesthesia allows the medical team to work efficiently and safely while ensuring the child has no negative memories of the experience.

Preparation for pediatric bone marrow biopsy includes fasting requirements specific to anesthesia. Typically, children should have nothing to eat for six hours before the procedure. Clear fluids (water, clear juice without pulp, plain gelatin) may be permitted up to 2-4 hours before anesthesia, but follow your medical team's specific instructions carefully. These fasting guidelines protect against aspiration of stomach contents during sedation.

Parents play an important role in preparing children emotionally. Depending on the child's age and maturity, you might explain that the doctors need to look at some special cells from inside their bones to help them feel better. Many children's hospitals have child life specialists who use play therapy, picture books, or virtual tours to familiarize children with what will happen. Bringing a favorite stuffed animal or blanket can provide comfort before and after the procedure.

After the procedure, children are monitored in a recovery area until the anesthesia wears off. This typically takes 30 minutes to an hour. Children may feel groggy, dizzy, or nauseous initially. Most children are ready to go home within a few hours of the procedure. Activity may be restricted for 24 hours, but most children bounce back quickly and return to normal play and school activities the next day.