First the stem cells are made to move from the bone marrow into the blood. To do this you will usually be given some chemotherapy, followed by a course of daily injections of a growth factor (G-CSF). The growth factor is given as an injection under the skin. Sometimes stem cells can be made to spill over into the blood using growth factors alone. You or a relative can be taught to give these injections, or you can go to your GP or the hospital to have them. Your blood will be tested regularly, and when there are enough stem cells in the blood, they will be collected.

Collecting the stem cells takes 3–4 hours. You will be asked to lie down on a couch and a drip will be put into the vein of each arm. Blood will be taken from one arm, through the drip, into a machine called a cell separator. The separator spins the blood to separate out the stem cells. These are collected, and the remaining blood is given back to you through the drip in your other arm. Sometimes a tube may be put into a vein at the top of your leg (instead of your arm) to collect the stem cells. If you already have a central line, or a PICC line, going into the main vein in your chest this can be used. The stem cells are then frozen until you have had the high-dose treatment.

Your donor will have their stem cells taken directly from the bloodstream in the same way except they are not given chemotherapy drugs. They will be given a short course of injections of a growth factor (G-CSF). This encourages the production of stem cells so that they spill over from the bone marrow into the blood. The stem cells are then collected from the blood, usually in one session, which takes 3–4 hours. Occasionally, if not enough stem cells are collected, the donor may have to come in for another collection. This can all be done as a day patient.