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 actual marrow for examination.
Iliac crest tap; Sternal tap
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 is removed from your pelvic or breast bone. Occasionally, another bone is selected.
Marrow is removed in the following steps:
If needed, you are given medicine to help you relax.
The health care 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 laboratory and examined 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 usually painful sucking sensation as the marrow is removed. This feeling lasts for only a few seconds.
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.
There may be some bleeding at the puncture site. More serious risks, such as serious bleeding or infection, are very rare.
Choby B. Bone marrow aspiration and biopsy. In: Pfenninger JL, Fowler GC, eds. Pfenninger & Fowler's Procedures for Primary Care. 3rd ed. Philadelphia, PA: Elsevier Mosby; 2010:chap 205.
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: Elsevier Saunders; 2011:chap 30.
Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.