On rare occasions, a donor is asked to donate a second time, either to the same patient or to a different one.
If you have blood stem cells removed, new ones will be generated to replace them, in much the same way as your blood is replaced when you make a blood donation. So it is possible to donate more than once. However, to minimize the strain on donors as far as possible, we try to keep those that have made a donation as backups, just in case their patient has a relapse and more blood stem cells are needed.
