For a recipient to be entered into a KPD Program, they must have a willing live donor. Most donor/recipient pairs are entered because of blood group and/or immunological incompatibilities. Other pairs may be seeking someone closer in age, size, or some other medical indication. In addition to pairs, non-directed donors can be entered. Non-directed donation (sometimes known as Altruistic or Good Samaritan donation) is a form of donation whereby a healthy living person donates a kidney to someone they do not know. All donors and recipients must undergo a complete standard evaluation and approval by the participating transplant centers before they can be entered into a KPD Program. Once entered, compatible pairings are identified using computer software. The software maximizes the number of matched pairs while providing additional consideration for specific populations such as children and highly sensitized recipients.