Bone Marrow Aspiration
and Biopsy

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Also known as: Bone Marrow; Bone Marrow Test
Formal name: Bone Marrow Aspiration; Bone Marrow Biopsy
Related tests: CBC; Differential; Reticulocyte Count; Blood Smear; Hemoglobin; Hematocrit; Platelet Count; WBC; RBC

At a Glance

Why Get Tested?

To evaluate the type, quantity, and maturity levels of the blood cells present in the marrow; to evaluate the fibrous structure of the marrow; and sometimes to collect a sample of marrow for more specific testing

When to Get Tested?

When a patient is anemic without an obvious cause and/or has a condition or cancer that may be affecting blood cell production; sometimes when a doctor is investigating a fever of unknown origin, especially when the patient is immuno-compromised

Sample Required?

A bone marrow sample collected primarily from the hip bone (pelvis); sometimes collected from the sternum in adults or the tibia (shin bone) in infants

Test Preparation Needed?

None

The Test Sample

What is being tested?

Bone marrow aspiration and biopsy are procedures used to collect and evaluate bone marrow. Bone marrow is a soft fatty tissue found inside the body’s larger bones. It has a honeycomb or sponge-like structure, consisting of a fibrous network that is filled with liquid. The liquid contains stem cells, blood cells in various stages of maturation, and “raw materials” such as iron, vitamin B12, and folate that are required for cell production. A bone marrow aspirate collects a liquid sample of cells that can be studied individually. A biopsy collects a cylindrical core sample that preserves the marrow’s structure. The biopsy shows the relationships of bone marrow cells to one another and the overall cellularity – the ratio of marrow cells to fat and other constituents present in the sample.

Red blood cells (RBCs), platelets, and five different types of white blood cells (WBCs) are produced in the marrow as needed, with the number and type of cell being produced at any one time based on the use of cells, loss, and a continual replacement of old cells. For instance, RBCs, which carry oxygen throughout the body, have a lifespan of about 120 days. The marrow paces RBC production at such a rate as to replace old RBCs that are taken out of circulation and maintain a relatively constant number in the blood. The marrow increases the rate of RBC production whenever the person’s number of RBCs decreases, due to such things as bleeding or hemolysis. The increased rate of production continues until there is a sufficient number of RBCs in the blood stream or until marrow production capacity is reached. If the need approaches this capacity, then an increased number of reticulocytes (immature RBCs) will be released into circulation as the marrow tries to keep up. If the need exceeds capacity, then the number of RBCs in the blood stream will decrease and the patient will become increasingly anemic, with symptoms such as pallor, fatigue, and shortness of breath due to decreased oxygen in the blood.

There are a variety of bone marrow disorders, cancers such as leukemia, vitamin and mineral deficiencies, inherited conditions, and diseases such as aplastic anemia that can affect the marrow’s ability to produce an adequate number of each of the different blood cell types and release them into circulation. These diseases may affect the overall number of cells produced, the proportion of cells produced, and/or the function of the cells. Some bone marrow disorders may lead to a deficiency of one or more cell types while others result in excess production of a specific type or of a specific clone of a cell - a single cell that reproduces without regulation.

Leukemia, for example, is a cancer of the blood cells. It results in the excessive production of one WBC type at the expense of other cell types and can lead to the release of large quantities of abnormal immature WBCs into the blood stream. These WBCs do not fight infection as other WBCs do and they leave the patient more vulnerable to illness. When leukemic WBCs crowd out RBC production in the bone marrow, the patient becomes anemic; when they decrease the number of platelets produced, they leave the patient vulnerable to excessive bruising and bleeding. Other conditions, such as vitamin B and folate or iron deficiency, lead to the creation of large or small or abnormally shaped RBCs and result in specific types of anemia. Another disorder, myelofibrosis, is characterized by the overgrowth of the fibrous network found in the marrow, compressing cells and leading to changes in red cell shape and changes in the cell counts.

Bone marrow aspiration and/or biopsy as a “test” includes both the collection of marrow samples and the evaluation of it under the microscope. Specialists, a pathologist and/or hematologist, microscopically examine slides containing stained smears of marrow samples – the fibrous network and fluid from a biopsy or the fluid from an aspiration. The number, size, and shape of each of the cell types present are examined, as are the proportions of mature and immature cells. If leukemia is present, or another cancer has spread into the marrow, it can be diagnosed through this examination, and the type and severity of the disease (the stage) can be established.

Depending on what condition(s) the doctor suspects, additional tests can be performed on the marrow sample. It may be cultured to look for viral, bacterial, or fungal infections that can cause a “fever of unknown origin.” In the case of leukemia, tests to determine the type of leukemia may be done. These include special stains or the determination of antigenic markers (immunophenotype) to show just what type of leukemia is present. Special stains may also be used to look for things such as excess iron storage in the marrow, and tests are sometimes ordered to detect chromosomal abnormalities.

How is the sample collected for testing?

The bone marrow aspiration and/or biopsy procedure is performed by a doctor or other trained specialist. Both types of samples may be collected from the hip bone. Marrow aspirations are sometimes collected from the sternum (breastbone) of adults. In infants, samples may be collected from the tibia (shin bone).

The most common collection site is the iliac crest (top ridge) of the back of the hip bone. Before the procedure, the patient’s blood pressure, heart rate, and temperature are measured and evaluated to make sure that they are within normal limits, and some patients are given a mild sedative. The patient is then asked to lie down on his stomach or side for the collection, and his lower body is draped with cloths so that only the area surrounding the site is exposed.

The site is cleaned with an antiseptic such as iodine and injected with a local anesthetic. When the site has numbed, the doctor inserts a needle through the skin and into the bone. For an aspiration, the doctor attaches a syringe to the needle and pulls back on the plunger. This creates vacuum pressure and pulls a small amount of marrow into the syringe. For a bone marrow biopsy, the doctor uses a special needle that allows the collection of a core (a cylindrical sample) of marrow.

Even though the patient’s skin has been numbed, the patient may feel brief but uncomfortable pulling and/or pushing pressure sensations during these procedures. After the needle has been withdrawn, a sterile bandage is placed over the site and pressure is applied. The patient is then usually instructed to lie quietly until his blood pressure, heart rate, and temperature are normal, and then to keep the collection site dry and covered for about 48 hours.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

How is it used?

The bone marrow biopsy and aspiration procedure provides information about the status of and capability for blood cell production. It is not routinely ordered and in fact the majority of people will never have one done. A bone marrow aspiration and/or biopsy may be ordered to help evaluate blood cell production, to help diagnose leukemia, to help diagnose a bone marrow disorder, to help diagnose and stage a variety of other types of cancer that may have spread into the marrow, and to help determine whether a severe anemia is due to decreased RBC production, increased loss, abnormal RBC production, and/or to a vitamin or mineral deficiency or excess. Conditions that affect the marrow can affect the number, mixture, and maturity of the cells, and can affect its fibrous structure.

 A bone marrow sample may also be evaluated and cultured for the presence of microorganisms such as fungi, bacteria, or mycobacteria (such as that which causes tuberculosis) when the patient has a fever of unknown origin. Additional marrow testing may be ordered when it is suspected that the patient has a chromosomal abnormality and/or a disorder associated with iron storage that may cause iron to accumulate in the marrow.

When a person is being treated for a cancer, a bone marrow aspiration and/or biopsy may be ordered to evaluate the response to therapy to determine whether suppressed marrow function is beginning to return to normal.

A CBC and reticulocyte count are frequently ordered along with the bone marrow aspiration/biopsy. The results are used to help evaluate cell production in the marrow and compare it to current cell populations in the blood.

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When is it ordered?

A bone marrow aspiration and/or biopsy may be ordered as a diagnostic procedure when, for example, one of the following is suspected:

It may be ordered when staging certain cancers. Staging is a careful and thorough examination and classification of how far the cancer has spread and what body organs are involved. These may include:

  • Hodgin's and Non-Hodgkins lymphomas
  • Small cell carcinoma of the lung (not frequently done anymore)

It may be ordered for culturing in some cases, such as:

  • When fever is present in HIV/AIDS or other immuno-compromised patients
  • In patients suspected of having infectious diseases such as Brucellosis or Typhoid Fever

A bone marrow biopsy and aspiration may also be ordered at intervals when a person is being treated for a cancer to evaluate whether marrow function is being suppressed and, if it is, when its function begins to recover.

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What does the test result mean?

With a bone marrow biopsy and aspiration the doctor is evaluating what is in the marrow in order to determine whether the cells found are normal and present in typical quantities, to determine whether there are cells present that should not be there, and to determine what is missing.

The training and expertise of the pathologist or hematologist evaluating the marrow samples allow her to sort through the marrow clues and determine what is happening in the marrow. In most cases, this information can confirm or rule out a diagnosis and bone marrow involvement, but it can also point out the need for further investigation. For instance, if there are a decreased number of RBCs in the blood and an increased number of reticulocytes, and a marrow evaluation shows that RBC production appears normal but increased, then the patient’s doctor knows that marrow production of RBCs has increased appropriately to meet a RBC demand. What she still doesn’t know is the reason for the demand. It could be due to an acute or chronic loss of RBCs, such as may occur with gastrointestinal bleeding, or due to acute or chronic RBC destruction, such as sometimes occurs with an artificial heart valve.

A patient with few RBCs and no increase in reticulocytes may have aplastic anemia with suppressed RBC production in the marrow. An evaluation of the bone marrow may confirm this condition, but it does not necessarily tell the doctor whether it is due to a bone marrow disorder, radiation, exposure to certain chemicals, cancer, cancer treatment, or due to a tuberculosis infection.

The presence of some abnormal cells can be characteristic of specific cancers or disorders, such as the Gaucher cell found with Gaucher’s disease or the foamy lipid-filled Niemann-Pick cell found with Niemann-Pick disease.

There may be masses of cells forming tumors in the marrow, such as can occur with multiple myeloma, and changes to or increases in the fibrous network that supports cellular production.

The doctor takes the information that she receives from the marrow evaluation and combines it with information from a clinical examination, blood tests, and a variety of other tests, such as imaging scans and X-rays, to reach a final diagnosis. It can be a straightforward process or it can be a complex diagnostic puzzle. Patients should stay involved in this process by talking to their doctor before and after a bone marrow biopsy and/or aspiration, asking her what her suspicions are, what kind of information she is hoping to obtain from the evaluation, and what follow-up tests might be indicated.

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Is there anything else I should know?

Complications from the bone marrow aspiration and/or biopsy procedure are rare, but some patients may have excessive bleeding at the collection site or develop an infection. Patients should tell the doctor about any allergies they have and about any medications or supplements they are taking prior to the procedure and should contact their doctor promptly if they experience persistent or spreading redness or bleeding at the site, a fever, or increasing pain.

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Common Questions

1.  Will I be put to sleep for a bone marrow aspiration and/or biopsy?

It is not usually necessary, but you may be given a sedative before the procedure.

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2.  How does a bone marrow aspiration and/or biopsy compare with a bone marrow collection for donation?

The collection process is similar, but the bone marrow donor goes through a physical and has blood tests done prior to the collection to make sure that he is healthy and that his sample will be compatible with the person to whom the marrow will be donated. The donor is usually put under general anesthesia during the collection because a larger amount of marrow must be obtained under sterile conditions. The sample is then processed, filtered and given to the transplant recipient through a vein. The stem cells in the donor sample travel through the blood stream to the marrow and, if all goes right, begin to create RBCs, WBCs, and platelets.

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

Pagana, Kathleen D. & Pagana, Timothy J. (© 2007). Mosby’s Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 183-188.

Corinne Goldberg, C. et. al (2008 April 7, Updated). Bone Marrow Aspiration and Biopsy. eMedicine [On-line information]. Available online at http://emedicine.medscape.com/article/207575-overview through http://emedicine.medscape.com. Accessed on 1/4/09.

Dugdale, D., Updated (2008 July 11, Updated). Bone marrow aspiration. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003658.htm. Accessed on 1/4/09.

Dugdale, D., Updated (2008 July 11, Updated). Bone marrow biopsy. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003934.htm. Accessed on 1/4/09.

Mayo Clinic Staff (2007 November 15). Bone marrow biopsy and aspiration. MayoClinic.com [On-line information]. Available online at http://www.mayoclinic.com/health/bone-marrow-biopsy/MY00305 through http://www.mayoclinic.com. Accessed on 1/4/09.

Riley, R. et. al An Illustrated Guide to Performing the Bone Marrow Aspiration and Biopsy. Virginia Commonwealth University Department of Pathology [On-line information]. PDF available for download at http://www.pathology.vcu.edu/education/lymph/How%20to%20Marrow.pdf through http://www.pathology.vcu.edu. Accessed on 1/4/09.

Thomas, Clayton L., Editor (1997). Taber’s Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition]. Pp 1163.

Sources Used in Previous Reviews

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby’s Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

Nanda, R. (2005 February 3, Updated). Bone marrow aspiration. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003658.htm.

Vergidis, D. (2004 June 28). Bone Marrow Aspiration and Biopsy. EMedicine [On-line information]. Available online at http://www.emedicine.com/med/topic2971.htm#section~procedure through http://www.emedicine.com.

Nanda, R. (2005 February 1, Updated). Bone marrow biopsy. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003934.htm.

(©1999-2003). Bone marrow aspiration and biopsy. Dr. Joseph F. Smith Medical Library [On-line information]. Available online at http://chclibrary.org/micromed/00040370.html through http://chclibrary.org.

Falck, T. (© 2003). Bone Marrow Biopsy. Emedicine Consumer Health [On-line information]. Available online at http://www.emedicinehealth.com/articles/4945-1.asp# through http://www.emedicinehealth.com.

(© 1995-2005). Bone Marrow Examination. Merck Manual Second Home Edition [On-line information]. Available online at http://www.merck.com/mmhe/sec14/ch170/ch170c.html?qt=%22bone%20marrow%22&alt=sh#fg170_1 through http://www.merck.com.

(© 1995-2005). Stem Cell Transplantation. Merck Manual Second Home Edition [On-line information]. Available online at http://www.merck.com/mmhe/print/sec16/ch187/ch187h.html through http://www.merck.com.

Sondheimer, N. (2005 April 20). Bone Marrow Aspiration And Biopsy. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/print/ency/article/003935.htm.

(April 2002). Bone and Marrow Stem Cell Transplantation: Leukemia, Lymphoma, and Myeloma. The Leukemia and Lymphoma Society [On-line information]. PDF available for download at http://www.leukemia-lymphoma.org/attachments/National/br_1018986496.pdf through http://www.leukemia-lymphoma.org.