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.

See also:

• Bone marrow biopsy
• Bone marrow culture

Iliac crest tap; Sternal tap

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

The health care provider will clean the skin and apply a numbing medicine (local anesthesia) to the area and surface of the bone. Next, 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.

The bone marrow fluid is examined under a microscope.

Tell the health care provider:

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

You must sign a consent form for the procedure.

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.

On rare occasions, patients are given medicine to help them relax before this procedure.

Your doctor 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 disorders

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

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

• Blood-forming (hematopoietic) cells
• Connective tissues
• Fat cells

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

• Acute lymphocytic leukemia (ALL)
• Acute myelogenous leukemia (AML)
• Chronic lymphocytic leukemia (CLL)
• Chronic myelogenous leukemia (CML)

Abnormal results may also be due to:

• Disseminated bacterial or fungal infections
• Hodgkin's disease
• Lymphoma (Non-hodgkin's)
• Multiple myeloma
• Myelofibrosis
• Myelodysplastic syndrome (MDS)
• Primary thrombocytopenia
• Waldenstrom's macroglobulinemia

This test may help detect the causes of:

• Aplastic anemia
• Idiopathic thrombocytopenic purpura (ITP)

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

This test is often performed when there are problems with various types of blood cells. The person may be at increased risk for bleeding, infection, or other problems.

Hutchison RE, McPherson RA, Schexneider KI. Basic examination of blood and bone marrow. In McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 30.

Kaushansky K. Hematopoiesis and hematopoietic growth factors. In Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 159.