Bone Marrow Biopsy: Purpose and Results

What to expect when undergoing this test

A bone marrow biopsy is a procedure to remove a small sample of bone marrow, the spongy tissue in the center of your bones. A needle is inserted into the bone, typically in the large pelvic bone near the hip (though other sites may be used). This is done to diagnose certain conditions, including blood and bone marrow diseases like leukemias and lymphomas.

Often, a bone marrow biopsy to extract solid tissue is done at the same time as a bone marrow aspiration. With this, a sample of the liquid portion of the bone marrow is removed so it, too, can be evaluated.

This article discusses how and why the bone marrow biopsy is performed. It will help you to know what to expect if you need to have this biopsy, as well as possible risks and complications.

bone marrow biopsy

Verywell / Cindy Chung

Purpose of Test

Bone marrow is the spongy material found inside of long bones, the pelvis, and the breastbone. All types of the blood cells in your body are produced within it. The bone marrow biopsy sites most often used for this test include:

  • The posterior iliac crest, a part of your pelvic bone near the hip
  • The sternum, or breastbone
  • The shin bone, or tibia, in infants and children under age 2

There are a number of different reasons for why a healthcare provider may recommend a biopsy. They're all connected to the types of cellular material in your bone marrow.

What Bone Marrow Contains

A type of stem cells, called pluripotent, are the origin of all blood cells that develop in bone marrow through a process known as hematopoiesis. These blood cells include:

  • White blood cells, needed to fight infections from bacteria, viruses, and parasites, as well as cancer cells
  • Red blood cells that carry oxygen to all of the cells in the body
  • Platelets, a type of cell needed for blood clotting

Stem cells initially divide into two different groups:

Bone marrow also contains connective tissue and the materials that are important to the manufacturing of blood cells, such as iron, vitamin B12, and folic acid.

Indications for Bone Marrow Biopsy

A bone marrow biopsy will provide the samples needed to evaluate the different types of blood cells, such as the proportions of them in your blood. It also offers information to your healthcare providers about bone marrow structure.

Some special tests on the sample can be used to further identify and subtype any abnormal cells. This offers clues about the cause of unexplained anemia or bleeding, and may be used to diagnose some genetic conditions. A bone marrow biopsy may be done to find the reason for:

  • Abnormal (high or low) levels of red blood cells (anemia or polycythemia)
  • White blood cell levels that may point to leukopenia or leukocytosis
  • Platelet counts seen with some conditions, such as thrombocytopenia or thrombocytosis.

A complete blood count (CBC) can detect abnormal levels of blood cells, but the results do not explain why the levels are high or low. Further tests are needed to understand these findings, sometimes including the bone marrow biopsy.

Other reasons for a bone marrow biopsy may include:

  • Evaluation of a fever of unknown origin, which may indicate cancer in the absence of another cause
  • Investigation of abnormal bleeding or clotting
  • Diagnosis or further evaluation of the subtypes of bone marrow cancers, such as leukemias and lymphomas, when a diagnosis cannot be made from circulating cancer cells
  • Evaluation to see if some cancers have spread to the bone marrow
  • Making decisions on cancer treatment based on the progress of a cancer or bone marrow disease
  • Assessment of iron overload conditions and to monitor iron levels
  • Identification of stem cell disorders and some rare genetic syndromes

By looking at a sample of bone marrow, healthcare providers can determine if too many of one type of blood cell are being made, or if the bone marrow contains tumors or fibrosis that crowds out the normal production of these cells. Findings can help zero in on diagnoses such as:

Limitations of Bone Marrow Biopsy

There are limitations to this type of biopsy. Among them is the bone marrow biopsy site itself, because bone marrow contents may vary in different regions of your body. An aspiration and biopsy done at one site may not be representative of the whole, or it may miss focal areas of bone marrow involvement with tumor or other conditions.

The technique and skill of the healthcare provider also affect the procedure and the quality of the samples obtained. For example, bleeding is the most common side effect of a bone marrow biopsy, which may present a challenge when a person has a low platelet count.

Comparing Bone Marrow Biopsy to Other Tests

Unlike the CBC and peripheral smear, which look at mature blood cells in the circulation, a bone marrow biopsy gives important information about blood cells in all stages of development.

It also can provide evidence of bone marrow disease, such as fibrosis, that cannot be detected with peripheral blood tests.

What's the Difference Between Bone Biopsy and Bone Marrow Biopsy?

A bone biopsy is done to take a sample of bone cells to evaluate the bone tissue itself for cancer. The bone marrow biopsy needle goes through the bone and into bone marrow. It is done to test for other types of cancers and conditions.

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.

Bone Marrow Biopsy Risks

The most common side effect of a bone marrow aspiration and biopsy is bleeding. This is uncommon overall—it happens in less than 1% of cases—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.

Apart from bleeding, other risks may include:

  • Infection, due to the opening in the skin where the bone marrow biopsy needle enters. It's especially true for people with a reduced number of infection-fighting white blood cells.
  • Persistent bone marrow biopsy pain, in some people.
  • A small risk of damage to nearby structures when a bone marrow aspiration is done at the breastbone (sternum). This is due to the close proximity of the heart and lungs.
  • A small risk of side effects from, or an allergic reaction to, the sedation medications given for the procedure or to the local anesthetic used to numb the site where the needle is placed.

Contraindications

If you have a very low platelet count, the procedure may need to be delayed or you may need a platelet transfusion before your bone marrow biopsy.

If you have a very low white blood cell count, the procedure may be delayed or you may need medication to increase counts before the test is done.

Before the Test

Your healthcare provider will discuss the bone marrow biopsy procedure with you and make you aware of potential risks. They will:

  • Ask about medications, over-the-counter remedies, or supplements you take
  • Take a family history from you, focusing on any history of bleeding disorders
  • Ask you about any allergies, including an allergy to local anesthetics or to latex
  • Confirm if 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 concerns you have about the procedure.

Timing

The amount of time it takes to perform a bone marrow aspiration and biopsy is about 10 minutes. However, you should plan on dedicating at least an hour or two to the procedure.

This will include time needed for any sedation medications to take effect, for preparing the bone marrow biopsy site, and monitoring after the procedure to make sure you are ready to return home.

Location

A bone marrow test is usually done as an outpatient procedure through a hematologist/oncologist, but it 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 to reduce discomfort at the site of the procedure after it is done.

Food and Drink

Healthcare providers vary in their recommendations, but some ask that you not eat beginning at midnight on the night prior to the procedure. Drinking clear liquids such as water is usually approved, but talk with your healthcare provider.

Medications

You may be asked to stop some medications before your bone marrow test, such as blood thinners, aspirin, or nonsteroidal anti-inflammatory drugs like Advil (ibuprofen). Sometimes the risk of stopping blood thinners is greater than the risk of bleeding due to 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 healthcare provider about any medications before you have the test.

Bone Marrow Biopsy Cost

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 practitioner performing the test will bill for the procedure, a test that currently runs between $1,000 and $6,000, depending on the facility and area where you live.

It also may depend on what type of specialist performs it. As one example, a 2021 study from one rural New York hospital compared the costs based on the type of provider completing the test and found the average was $5,254 when interventional radiology specialists did the bone marrow aspiration and biopsy, compared with $413 in hematology-oncology.

The pathologist responsible for examining the samples in a laboratory typically 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 specialized molecular tests are done.

Keep in mind that procedures done at a hospital are usually costlier 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 healthcare provider is concerned about a leukemia, lymphoma, or the 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 bring your mobile phone, or 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, the biopsy site will likely be sore, and you will probably be more comfortable as a passenger in the car than as the driver.

During the Test

During your bone marrow biopsy, you will be attended to by the hematologist/oncologist and other healthcare providers assisting with the procedure. A laboratory technician may also be present to assist in collecting the sample, making blood smears, and delivering these to the laboratory.

Pre-Test

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, an IV will be placed. Oral sedation may 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 bone marrow biopsy site also will determine some elements of the procedure.

  • A hip biopsy is done in two parts, the aspiration and then the biopsy. The back of the hip (posterior iliac crest) is used more commonly than the front. This is by far the most common site used for a bone marrow examination.
  • 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 children or infants under age 2, as it provides an insufficient sample of cells in adults.

The area where the biopsy will be performed will be cleansed with a disinfectant and the area draped with sterile towels. The surface of the skin will then be numbed locally with a lidocaine injection, which will cause you to feel a sting.

After making a small incision in the skin, a hollow needle is inserted. You will feel pressure as it enters your skin, then a sharp, momentary sting when the needle enters the bone. The needle has an internal rod called a bone trocar that will then be removed.

The aspiration is done first and is usually responsible for most bone marrow biopsy pain. The healthcare provider attaches a syringe to the needle after removing the trocar and withdraws fluid. This often causes a deep ache, but fortunately, it only takes a few seconds. If the sample does not have enough fluid, another sample may be needed from another site.

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

Post-Test

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. You will be asked to lie down for 10 to 15 minutes before leaving. You may note some soreness as the local anesthetic wears off.

After the Test

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 doesn't get wet. Your healthcare provider 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.

You will be able to take most of your medications as soon as your bone marrow examination has been completed, but you should talk to your healthcare provider about when to resume taking any blood thinners and medications such as aspirin or anti-inflammatories.

Managing Bone Marrow Biopsy Pain

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.

In most cases, you can expect the pain to resolve in a few days.

When to Call Your Healthcare Provider

It's important to call your healthcare provider if:

  • You have any bleeding from the site that does not stop with pressure on the wound
  • You develop signs of infection, such as a fever, redness, swelling, or discharge
  • You have significant pain that is not going away or getting worse

Interpreting Results

The samples from your bone marrow will be reviewed under a microscope in the pathology lab. Some results may be available shortly after your biopsy, but others can take longer. Those of chromosome studies, for example, may take two weeks or more to come back.

More than a dozen cell types will be evaluated and results will be compared to reference ranges, which vary widely and can differ depending on age. Comparing your results to these ranges, as a patient, is not entirely useful, as the set of results as a whole is what's telling.

A pathologist and your healthcare provider will be able to discuss the results with you.

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, meaning the number of blood cells relative to other components of bone marrow such as fat (this can vary at different ages)
  • Infiltrates, or 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

Bone Marrow Aspiration Results

Evaluation of the liquid bone marrow sample can reveal:

  • 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). This is 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, blasts may make up to 20% to 30% of the type of white blood cells in cases of acute lymphocytic leukemia and acute myelocytic leukemia. While this may be diagnostic of acute leukemia, further testing will be needed to determine the subtype of the leukemia.
  • Whether abnormal cells such as leukemia cells or tumor cells are present

Special Tests

In addition to the samples being examined, special tests may be done on them 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
  • Molecular testing, needed to determine subtypes and molecular characteristics of the cancer that are important in choosing the best treatment options
  • 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. Depending on your results, consider whether a second opinion might be appropriate before beginning any treatment.

A Word From Verywell

Scheduling a bone marrow biopsy can be a new experience. Understanding what the test will be like and asking questions about the procedure are an important part of being an advocate for your own health care. It will help you to make the best decisions about your care.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Indranil Mallick, MD
 Indranil Mallick, MD, DNB, is a radiation oncologist with a special interest in lymphoma.