Definition of Bone marrow aspiration:

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

How the test is performed:

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.

A laboratory specialist looks at the bone marrow fluid under a microscope.

How to prepare for the test:

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.

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 sometimes painful sucking sensation as the marrow is removed. This feeling lasts for only a few moments.

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

Why the test is performed:

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.