Stem cells can be collected from the bone marrow or the blood. If stem cells are collected from the bone marrow it is called a harvest. If stem cells are collected from the peripheral blood it is called apheresis.
Bone Marrow (Harvest)
Bone marrow is the spongy tissue located in the center of bones. The tissue has a high content of stem cells which is why bone marrow is the first choice for harvesting. Pelvic bones are generally used in bone marrow harvest because they contain more marrow than any other bone.
Bone marrow harvest is completed in the operating room under general anesthesia. A hollow needle and syringe is used to remove bone marrow from the donor's hip bone. The needle is inserted into the center of the hip bones in several different areas and collects the marrow. The main side effect from bone marrow harvesting is soreness or discomfort in the area where the marrow was removed.
Peripheral Blood (Apheresis)
Stem cell apheresis is a second option when gathering stem cells. Under normal circumstances, few stem cells are found in the blood; yet, certain medications can be given prior to the procedure which cause stem cells to grow faster and move from the bone marrow into the blood. Even with the medication, a donor will usually need to commit to several sessions in order to gather the recommended amount of stem cells.
During apheresis, a catheter (thin, flexible tube) is placed within a vein in the donor's arm. The catheter is connected to a blood cell separator. This machine will separate the stem cells from the donor's blood; pump the stem cells into a bag; and return the blood to the donor's body. Most donors will have two to five sessions lasting four to six hours each. The procedure is not painful; however, during the procedure donors may feel lightheaded or dizzy due to the changes in blood volume.