The transplant team will consider many different people as potential donors. Immediate family, relatives, or close friends are preferred, since they are most involved in the potential recipient's health. The donor must have a compatible blood type and must also be similar in size to the recipient. (Note: if you want to donate to a loved one but are not compatible, you may still be able to donate through a paired exchange.)

Most important, the donor must be in good physical and mental health, with no significant history of major medical problems. Generally speaking, the transplant team will consider donors in good health between the ages of 20 and 50 for a living liver donation and between the ages of 18 and 65 for a living kidney donation. The team evaluates donors outside the upper age limit on a case-by-case basis.

Want to know more about becoming a living donor? Take the first step by completing a health questionnaire.