The number of stem cells circulating in peripheral blood is normally low. Therefore, prior to stem cell collection, donors are administered growth factor medications, known as granulocyte colony-stimulating factor (G-CSF), to increase the stem cell count. Peripheral stem cells are separated from the donor's blood using specialized apheresis equipment. After the stem cells are separated, the remaining blood components are returned to the donor. This procedure typically lasts 4-6 hours and may need to be repeated over several consecutive days depending on the patient's requirements. In autologous transplants, the patient themselves serves as the peripheral stem cell donor. Once infused into the patient, these collected stem cells engraft in the bone marrow. In this type of transplant, engraftment and subsequent blood production usually begin earlier than with bone marrow transplants, typically within 10-20 days.