The bone marrow test is usually done as an office procedure. The patient is usually asked to lie prone (on his abdomen) or to one side. The marrow sample is usually taken from the hip bone. The skin is cleansed with an antiseptic, and a local anesthetic is injected to make the skin numb.
For bone marrow aspiration, a thin needle is inserted into the bone and advanced inwards with a slow rotating movement till the marrow is reached. A small amount of liquid marrow is withdrawn.
For a bone marrow biopsy, a thicker biopsy needle is inserted into the bone. The core of the biopsy needle is removed, and the needle is pressed forward into the marrow and rotated in both directions. A small sample of the bone marrow enters into the needle.After either procedure the needle is removed and pressure is applied over the area to stop any bleeding. The area may be covered with a small antiseptic dressing. The patient is asked to keep lying down for 10-15 minutes. He or she is then free to leave.