Definition

Bone marrow is the soft tissue inside bones that helps form blood cells. It is found in the hollow part of most bones. Bone marrow aspiration is the removal of a small amount of this tissue in liquid form for examination.

Bone marrow aspiration is not the same as bone marrow biopsy. A biopsy removes a core of bone tissue for examination.

How the Test is Performed

Bone marrow aspiration may be done in your health care provider's office or in a hospital. The bone marrow is removed from your pelvic or breast bone. Sometimes, another bone is selected.

Marrow is removed in the following steps:

  • If needed, you are given medicine to help you relax.
  • Your provider cleans the skin and injects numbing medicine into the area and surface of the bone.
  • A special needle is inserted into the bone. The needle has a tube attached to it, which creates suction. A small sample of bone marrow fluid flows into the tube.
  • The needle is removed.
  • Pressure and then a bandage are applied to the skin.

The bone marrow fluid is sent to a lab and examined under a microscope.

How the Test will Feel

You will feel a sting and slight burning sensation when the numbing medicine is applied. You may feel pressure as the needle is inserted into the bone, and a sharp and usually painful sucking sensation as the marrow is removed. This feeling lasts for only a few seconds.

How to Prepare for the Test

Tell your provider:

  • If you are allergic to any medicines
  • If you are pregnant
  • If you have bleeding problems
  • What medicines you are taking

Normal Results

The bone marrow should contain the proper number and types of:

  • Blood-forming cells
  • Connective tissues
  • Fat cells

References

Bates I, Burthem J. Bone marrow biopsy. In: Bain BJ, Bates I, Laffan MA, eds. Dacie and Lewis Practical Haematology. 12th ed. Philadelphia, PA: Elsevier; 2017:chap 7.

Choby BA. Bone marrow aspiration and biopsy. In: Fowler GC, ed. Pfenninger and Fowler's Procedures for Primary Care. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 220.

Vajpayee N, Graham SS, Bem S. Basic examination of blood and bone marrow. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 31.

Risks

There may be some bleeding at the puncture site. More serious risks, such as serious bleeding or infection, are very rare.

What Abnormal Results Mean

Abnormal results may be due to cancers of the bone marrow, including:

Abnormal results may also be due to other causes, such as:

Why the Test is Performed

Your provider may order this test if you have abnormal types or numbers of red or white blood cells or platelets on a complete blood count.

This test is used to diagnose:

  • Anemia (some types)
  • Infections
  • Leukemia
  • Other blood cancers and disorders

It may help determine whether cancers have spread or responded to treatment.

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