A bone marrow aspiration and biopsy remove a small amount of bone and a small amount of fluid and cells from inside the bone (bone marrow). It is often done to find the reason for many blood disorders and may be used to find out if cancer or infection has spread to the bone marrow. Some conditions are associated with unhealthy bone marrow. If preliminary blood tests show abnormal levels of white or red blood cells or platelets, your doctor may order a bone marrow aspiration. Bone marrow diseases, such as myelofibrosis or myelodysplastic syndrome. The bone marrow exam typically takes about 10 minutes. Extra time is needed for preparation and post-procedure care, especially if you receive intravenous (IV) sedation. The total time for the procedure is about 30 minutes.