When you register with DKMS, we analyse some of your tissue (HLA) characteristics, necessary to find a matching donor for a patient. We do not check for any infections other than cytomegalovirus (CMV). Only when you are found to match a particular patient do we check for specific viruses, such as HIV, hepatitis B and C. However, not every donor will be a match and even if they are, this could be several years after they register.