The first step in producing BMC is to collect bone marrow aspirate through a minimally invasive method that uses a needle to remove bone marrow from a large bone, such as the pelvic bone. The procedure is generally done under local anesthesia, sedation or with general anesthesia. The aspirate is then put through processing that uses a centrifuge. Bone marrow processing methods vary widely and can affect the number and quality of cells, especially in terms of useful stem and progenitor cells.