Also Known As
Bone Marrow
Bone Marrow Test
Formal Name
Bone Marrow Aspiration; Bone Marrow Aspirate; Bone Marrow Biopsy; Bone Marrow Trephine Biopsy
This article was last reviewed on
This article waslast modified on 29 January 2019.
At a Glance
Why Get Tested?

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

When To Get Tested?

When a patient is anaemic without an obvious cause and/or has a condition or cancer that may be affecting blood cell production; as a means of helping find out how advanced a cancer is; 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 (breast bone) in adults or the tibia (shin bone) in infants

Test Preparation Needed?


On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

Bone marrow aspiration and biopsy are procedures used to collect and test 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 network of fibres 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 material 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 being dependent 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 alters RBC production so that it can 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 haemolysis. 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 anaemic, with symptoms such as pale skin (pallor), tiredness, and difficulty breathing due to reduced oxygen in the blood.

A variety of bone marrow diseases, cancers such as leukaemia, vitamin and mineral deficiencies, inherited conditions, and diseases such as aplastic anaemia 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 total number of cells produced, the proportion of different 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.

Leukaemia, for example, is a cancer of the blood cells. It results in the excessive production of one (or a few) WBC types 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 may not fight infection as other WBCs do and leave the patient more vulnerable to infections. When leukaemic WBCs exceed RBC production in the bone marrow, the patient becomes anaemic; when they decrease the number of platelets produced, they leave the patient vulnerable to excessive bruising and bleeding. Other conditions, such as vitamin B or folate deficiency lead to anaemia with large red blood cells and sometimes changes in white blood cells and platelets. Iron deficiency causes anaemia with small red blood cells, sometimes abnormally shaped.. Another disorder, myelofibrosis, is characterised by the overgrowth of fibres 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 haematologist, examine under a microscope glass 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 leukaemia 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 worked out.

Depending on what the doctor thinks may be wrong, additional tests can be done on the marrow sample. In the case of leukaemia, tests to work out the type of leukaemia may be done. These include special stains or the determination of antigenic markers (immunophenotype or “cell markers”) to show just what type of leukaemia is present. Special stains may also be used to look for things such as how much iron is stored in the marrow, and tests are sometimes used to detect chromosomal or genetic abnormalities. Rarely, marrow may be used to look for infections that can cause a “fever of unknown origin”.

How is the sample collected for testing?

The bone marrow aspiration and/or biopsy procedure is done by a doctor or other trained specialist. Both types of samples may be collected from the pelvis. 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 pelvis. Before the procedure, patients are given a local anaesthetic (lignocaine) and/or nitrous oxide gas. A mild sedative may be prescribed depending on the local policy of the hospital.

The patient is usually asked to lie down on their side curled up for the procedure. The site is cleaned with an antiseptic and injected with a local anaesthetic. When the site is numb, 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, pulling a small amount of marrow into the syringe – usually less than a teaspoonful. 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, it is usual to 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 for a few minutes, and then to keep the collection site dry and covered for about 48 hours.

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

No test preparation is needed.

Accordion Title
Common Questions
  • 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 used and in fact the majority of people will never have one done. A bone marrow aspiration and/or biopsy may be requested to help measure blood cell production, to help diagnose leukaemia, to help diagnose a bone marrow disease, to help diagnose and find out whether a variety of other types of cancer have spread into the marrow, and to help discover whether a severe anaemia 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 used when it is suspected that the patient has a chromosomal abnormality and/or a disease which has brought an increase in iron storage in the marrow.

    When a person is being treated for a cancer, a bone marrow aspiration and/or biopsy may be requested to find out the response to therapy and whether suppressed marrow function is beginning to return to normal, or use special tests to look for tiny amounts leukaemia

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

  • When is it requested?

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

    It may be used for ‘staging’ certain cancers. ‘Staging’ is a careful and thorough examination which helps the doctor record how far the cancer has spread and what body organs are also affected. These may include:

    It may be used to look for infection 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 used at intervals when a person is being treated for a cancer to find out whether marrow function is being suppressed and, if it is, when its function begins to recover.

  • What does the test result mean?

    With a bone marrow biopsy and aspiration the doctor is looking at what is in the marrow in order to find out whether the cells found are normal and present in normal quantities, to find out whether there are cells present that should not be there, and to look at what is missing.

    The training and experience of the pathologists or haematologists evaluating the marrow samples allows them to sort through the marrow clues and find out 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 they still don’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 anaemia 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 tumours in the marrow, such as can occur with multiple myeloma, or changes to or increases in the fibrous network that supports cellular production.

    Doctors take the information they receive from the marrow evaluation and combine 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 what their suspicions are, what kind of information they hope to obtain from the evaluation, and what follow-up tests might be indicated.

  • Is there anything else I should know?

    Complications from the bone marrow aspiration and/or biopsy procedure are very 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 drugs or supplements they are taking before 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.

  • 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 depending on hospital policy.

  • 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 examination and has blood tests done prior to the collection to make sure that they are healthy and that the sample will be compatible with the person to whom the marrow will be donated. The donor is usually put under general anaesthesia during the collection because a larger amount of marrow must be obtained - often around a litre- 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.