A bone marrow aspiration is done under local anaesthesia. The procedure involves passing a wide-bore needle from the skin into the centre of the bone to get a small sample of the bone marrow. It is usually done on the chest bone, hip bone, or thigh bone. The bone marrow sample is then sent for biopsy, which helps to diagnose whether your bone marrow is making an adequate amount of healthy blood cells. This diagnostic test is performed in suspected blood-related disorders, cancers, or fevers of unknown cause.