What is a Bone Marrow Biopsy and Aspiration?

What to Expect With Your Bone Marrow Biopsy

Technician performing bone marrow transplant
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A bone marrow aspiration and biopsy is a procedure that obtains a sample of bone marrow to evaluate the different types of blood cells (white blood cells, red blood cells, and platelets) as well as the structure of the bone marrow. It can be used to diagnose diseases of the blood and bone marrow such as leukemias and lymphomas, figure out the cause of unexplained anemia or bleeding, and diagnose some genetic conditions. The most common site for a bone marrow biopsy is the large pelvic bone near the hip (posterior iliac crest), but a sample may also be taken from the sternum (breastbone), or, in infants, the shin bone (tibia). A bone marrow study can be uncomfortable, but the actual procedure usually takes only about 10 minutes.

In addition to providing information about the types and proportions of blood cells as well as bone marrow structure, special tests on the sample obtained can be used to further identify and subtype any abnormal cells.

Purpose of Test

A bone marrow biopsy is often ordered when a person has symptoms of a high or low level of one of the types of blood cells, or laboratory findings that suggest leukemia or another blood or bone marrow disorder. High or low levels of any of the types of blood cells on a complete blood count do not explain why the levels are high or low. By looking at a sample of bone marrow, physicians can determine if too many of one type of blood cell are being made, or if the bone marrow contains tumor or fibrosis that crowds out the normal production of these cells. Since the bone marrow is the site of production, a bone marrow test may be used to diagnose blood-related cancers when there are not enough circulating cancer cells to make the diagnosis.

To better understand why a bone marrow aspiration and biopsy may be ordered, it's helpful to understand what is present in the bone marrow.

Contents of the Bone Marrow

The bone marrow is the spongy material found inside of long bones, the pelvis, and the breastbone, that produces all of the types of blood cells, and consists of cells in all stages of development (unlike peripheral blood).

Pluripotential stem cells are the origin of all of the blood cells that develop through a process called hematopoiesis. Stem cells initially divide into two different cells the myeloid cell line and the lymphoid cell line. Cells in the myeloid line differentiate into the types of white blood cells known as neutrophils, eosinophils, basophils, monocytes, red blood cells, and platelets (platelets are actually fragments of large cells called megakaryocytes). Cells in the lymphoid line differentiate into T lymphocytes (T cells) and B lymphocytes (B cells). The immature form of white blood cells are called blasts (lymphoblasts and myeloblasts). Bone marrow also contains connective tissue and the materials that are important in the manufacture of blood cells, such as iron, vitamin B12, and folic acid.

The different types of blood cells have different functions:

  • White blood cells: To fight infections with bacteria, viruses, and parasites, as well as cancer cells
  • Red blood cells: To carry oxygen to all of the cells in the body
  • Platelets: To aid in blood clotting

Reasons Why a Bone Marrow Study May Be Ordered

There are a number of different reasons why a doctor may recommend a bone marrow biopsy. Some of these include:

  • An abnormal level (high or low) of red blood cells (anemia or polycythemia), white blood cells (leukopenia or leukocytosis), or platelets (thrombocytopenia or thrombocytosis)
  • To evaluate a fever of unknown origin (a fever that persists without any obvious cause)
  • Abnormal bleeding or clotting
  • Known cancers that begin in the bone marrow, including leukemias, lymphomas, or multiple myeloma to further evaluate and determine subtypes of the cancer
  • To see if some cancers have spread to the bone marrow
  • To follow the progress of a cancer or bone marrow disease, either to decide when to initiate treatment, or to monitor the results of treatment
  • To evaluate iron overload conditions and monitor iron levels
  • Stem cell disorders
  • Some rare genetic syndromes

Conditions That May Be Diagnosed

Findings on a bone marrow exam may include abnormal numbers of one or more types of blood cells, an abnormal ratio of the blood cells, replacement of the bone marrow with tumor, fibrosis of the bone marrow, and more. These findings, along with specialized tests done on the bone marrow sample may be used to diagnose conditions such as:


Since the contents of the bone marrow may vary in different regions, an aspiration and biopsy done in one region may not be representative of the whole or may miss focal areas of bone marrow involvement with tumor or other conditions. The technique is also dependent on the skill of the physician performing the procedure and the quality of the samples obtained. Since bleeding is the most common side effect of the procedure, it may be challenging when a person has a low platelet count.

Comparison to Other Tests

Unlike a complete blood count (CBC) and peripheral smear that looks at mature blood cells in the circulation, a bone marrow biopsy gives important information about blood cells in all stages of development. It can also provide evidence of bone marrow disease (such as fibrosis) that cannot be detected on peripheral blood.

Associated Tests

In addition to a pathologist looking at a bone marrow specimen under the microscope to examine the particular cells present, specialized tests such as flow cytometry, chromosomal studies, and more may be done to gain further information (see below under interpreting results).

Risks and Contraindications

As with any medical test, there are potential risks to a bone marrow biopsy as well as reasons why the test may not be recommended (contraindications).

Potential Risks

The most common side effect of a bone marrow aspiration and biopsy is bleeding. This is uncommon overall (less than 1 percent) but is more likely to occur if a person's platelet count is low. In this case, however, the benefits of a diagnosis may still outweigh any potential risk. Infection (due to the opening in the skin where the needle enters) may also occur, especially in people who are at a greater risk of infection due to a reduced number of white blood cells. Persistent pain after the procedure may also occur for some people. These risks can be reduced by checking a complete blood count prior to the procedure.

When a bone marrow aspiration is performed on the breastbone (sternum) there is a small risk of damage to nearby structures due to the close proximity of the heart and lungs.

There is also a small risk of side effects or an allergic reaction to the medications given to make you drowsy or to the local anesthetic (or heavier sedation in children) used to numb the site where the needle is placed.


In people who have a very low platelet count, the procedure may need to be delayed, or platelet transfusions may be given prior to the biopsy. For those who have a very low white blood cell count, the procedure may also be delayed, or medications may be given to increase counts.

Before the Test

When your doctor recommends a bone marrow biopsy, she will discuss the procedure and any potential risks. She will want to know about any medications, over-the-counter remedies, or supplements you are taking, and will ask you whether you or anyone in your family has a history of bleeding disorders. She will also ask you about any allergies, including an allergy to local anesthetics or to latex, and whether you are pregnant or if there is a chance you are pregnant. During this visit, it's important to ask any questions you have and talk about any anxiety you have about the procedure.


While the amount of time it takes to perform a bone marrow aspiration and biopsy is only around 10 minutes, you should plan for spending at least an hour or two on the day of the procedure. This will include time for a nurse to provide you with medications to relax you if needed (and for sedation in the case of a child), time to clean and anesthetize the area, and time after the procedure to make sure you are comfortable to return home.


A bone marrow test is usually done as an outpatient procedure at a hematologist/oncologist's office, but may also be done at a hospital.

What to Wear

Most of the time, a person will be asked to change into a gown before the procedure. It's a good idea to dress in loose clothing (loose around the hips if your procedure will be done on your hip or loose over your breastbone if the procedure will be done on your sternum), to reduce discomfort at the site of the procedure after it is done.

Food and Drink

Physicians vary in their recommendations, but some ask that you not eat beginning at midnight the night prior to the procedure. Drinking clear liquids such as water is usually alright, but talk to your doctor about her recommendations.


You may be asked to stop some medications before your bone marrow test, such as blood thinners, aspirin, or nonsteroidal anti-inflammatory drugs such as Advil (ibuprofen), but talk to your doctor. Sometimes the risk of stopping blood thinners is greater than the risk of bleeding with the procedure. Keep in mind that some medications may need to be discontinued a week or more before the test. Some vitamins and dietary supplements can also increase the risk of bleeding, and it's important to talk to your doctor about any of these preparations you use before the test.

Cost and Health Insurance

Most health insurance companies will cover a bone marrow aspiration and biopsy, but in some cases, prior authorization may be required. You will likely be billed separately for different aspects of the test. The physician performing the test will bill for the procedure, a test that currently runs between $1,700 and $2,800 depending on the facility and area where you live. The pathologist usually bills separately for any tests run on the sample. This figure can vary significantly depending on whether the sample is only viewed under the microscope or whether specialized molecular tests are done. Procedures done at a hospital are usually more costly than those done in a clinic.

For those who are uninsured, there are several options, and it's important to talk to a social worker at your clinic or hospital if you are concerned about the cost. Some clinics offer discounts for those who do not have insurance and set up a payment plan ahead of time. If your doctor is concerned about a leukemia, lymphoma, or spread of other cancers to the bone marrow, there are a number of ways to find financial assistance if you have cancer.

What to Bring

On the day of your appointment, you should bring your health insurance card and any paperwork you were asked to fill out. It's always a good idea to pack a book or magazine in the event there is a delay in the start of the procedure.

Other Considerations

If you aren't given sedation, you may be able to drive yourself to the appointment. That said, your hip will likely be sore, and you will probably be more comfortable as a passenger in the car than as the driver. Having a companion with you can help you pass the time and provide support during an anxious time.

During the Test

During your bone marrow test, you will be attended to by a hematologist/oncologist (or other trained specialists) performing the procedure, and a nurse. A laboratory technician may also be present to assist in collecting the sample, making blood smears, and delivering these to the laboratory.


At the start of the test, you will be asked to sign a consent form indicating that you understand the purpose of the test and the potential risks. If you will be receiving IV sedation (such as with children) an IV will be placed. Oral sedation may also be given for adults who are anxious about the procedure. Your vital signs (heart rate, blood pressure, and temperature) will be taken, and you will again be asked whether you have any concerns.

Throughout the Test

In the procedure room, you will be asked to lie on your side, back, or abdomen, depending on the site of the biopsy. The area where the biopsy will be performed will be cleansed with a disinfectant and the area draped with sterile towels.

(A hip biopsy is done in two parts, the aspiration and then the biopsy. A breastbone (sternum) biopsy is done only in adults and children over the age of 12, and includes only an aspiration. A tibia (shin) biopsy is done only in infants less than one year of age as it provides insufficient cells in adults. With a hip procedure, the back of the hip (posterior iliac crest) is used more commonly than the front.)

The surface of the skin will then be numbed locally with lidocaine, and after making a small incision in the skin, a hollow needle is inserted. (The needle has a removable rod called a bone trocar inside that will be removed after the needle enters the bone). You will feel a sting as the local anesthetic is injected, and then pressure as the needle is inserted. When the needle enters the bone you will feel a sharp sting for a moment, as the local anesthetic does not reach to the bone). The bone marrow aspiration and biopsy are then done as two separate procedures, to obtain samples of both the liquid and solid parts of the bone marrow.

The aspiration is done first, and is usually the most painful part of the procedure. The physician attaches a syringe to the needle after removing the trocar, and withdraws fluid. This often causes a deep ache, but fortunately, only takes a few seconds. If the sample does not have enough fluid, another sample may need to be taken from another site.

With a bone marrow biopsy, a thicker needle is inserted into the bone with a twisting motion to take a core sample of the bone marrow. The biopsy often causes sharp pain for a few seconds while the sample is being taken.


When the procedure is done, the needle is removed and pressure is applied to the area to stop any bleeding. The area is then covered with an antiseptic dressing and you will be asked to lie down for another 10 to 15 minutes before leaving. You may note some soreness as the local anesthetic wears off.

After the Test

After you leave the clinic or hospital, you may feel some aching in the region of the biopsy for a few days. You should keep the biopsy site dry and covered for two days, and avoid showering, baths, or swimming during this time. You may give yourself a sponge bath or wash your hair in the sink or tub as long as the biopsy site stays dry. Your doctor may instruct you to inspect and change the dressing, but this can vary. You will be able to resume your regular diet as soon as the test is completed, as well as many of your activities. It's important, however, to avoid excessive activity or heavy lifting for the first few days after the biopsy.

When to Call

It's important to call your doctor if you have any bleeding from the site that does not stop with pressure on the wound, if you develop signs of infection such as a fever, redness, swelling, or discharge from the biopsy site, or if you have significant pain that is not going away or getting worse.

Managing Side Effects

You may feel achy in the region of your biopsy for a few days, and may be advised to use Tylenol (acetaminophen) or prescription pain medications to treat any discomfort. Most often, people are advised to avoid aspirin or nonsteroidal anti-inflammatory drugs such as Advil (ibuprofen) or Aleve (naproxen) as these can increase bleeding. Most of the time the achiness lasts only a day or two, but sometimes can last longer.

Interpreting Results

The samples from your bone marrow will be reviewed in the pathology lab. Some of these tests may be available shortly after your biopsy, but others can take longer. Chromosome studies, for example, may take two weeks or more before results are available.

Bone Marrow Aspiration Results

The sample from the bone marrow aspiration is looked at under the microscope, and can also be used for the special tests below. this includes:

  • The number of each type of blood cell.
  • The proportion of each type of blood cell relative to other blood cells in the marrow.
  • The myeloid/erythroid ration (ME ratio): The number of cells that are precursors of white blood cells compared with the number of cells that are precursors to red blood cells.
  • The maturity of cells: For example, if there is an increased number of blasts (immature cells) as seen with acute lymphocytic leukemia and acute myelocytic leukemia (in these conditions, blasts may make up 20 percent or 30 percent of the type of white blood cells).
  • Whether abnormal cells such as leukemia cells or tumor cells are present.

Bone Marrow Biopsy Results

The bone marrow biopsy also looks at the number and types of blood cells, but also gives important information about the structure of the bone marrow. Results include:

  • The numbers and types of white blood cells, red blood cells, and platelets at all stages of development (to determine if there are adequate numbers)
  • Cellularity: The number of blood cells relative to other components of bone marrow such as fat (this can vary at different ages)
  • Infiltrates: Whether anything abnormal is present in the bone marrow, such as cancer or an infection
  • Changes to the bone marrow stroma such as fibrosis
  • Changes to the bone, such as osteoporosis

Special Tests

Special tests may be done on the bone marrow sample depending on the possible diagnosis. These may include:

  • Tests to diagnose and stage leukemia, lymphoma, and myeloma, such as cytochemistry (flow cytometry and immunophenotyping), chromosomal studies, and molecular testing
  • Cultures and stains to look for certain viruses, bacteria, and fungi
  • Stains to look for iron overload


Follow-up after a bone marrow test will depend on the diagnosis and treatments that are recommended.

Other Considerations

The results of a bone marrow aspiration and biopsy, especially if a number of special tests are ordered, can be confusing. Not only do people sometimes need to cope with uncertainty or a frightening diagnosis, but it can feel like all of the answers are in a foreign language. Make sure to ask any questions you have, and ask again if you do not understand any part of your test. Being your own advocate requires understanding your medical condition, and this can take time with many blood and bone marrow conditions. Depending on your results, consider whether a second opinion might be appropriate before beginning any treatment.

A Word From Verywell

Scheduling your bone marrow biopsy can be very anxiety-provoking, as you consider both the possible discomfort of the procedure, and the possible diagnoses that could be found. This anxiety can persist after the procedure as well as some of the specialized studies can take more than two weeks until results are available. Understanding what the test will be like, asking questions about anything you don't understand, and educating yourself about any abnormalities found, can help you feel more in control of your care, and empowered as you make decisions going forward.

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