An examination of a sample of the soft tissues in the bones is done by a method called bone marrow aspiration. The spongy substance known as bone marrow is found inside the bones of the human body. Inside the bigger bones, the bone marrow is responsible for producing platelets, red blood cells, and white blood cells. Bone marrow aspiration only takes ten minutes to complete. However, the time-consuming parts are the planning and recovery. Both a hospital and a clinic are able to do the surgery. The test is performed by an oncologist or hematologist. When initial blood tests reveal low numbers of white blood cells, red blood cells, or platelets, doctors order the testing.