Kidney Paired Donation Graph Example
An example graph depicting 20 incompatible donor/recipient pairs, numbered 0 through 19. Each node (numbered circle) represents one donor/recipient pair, and each edge (line connecting two nodes) indicates that a paired donation would be possible between the two connected pairs.
Effect of Donor Blood Type
Pair 4 (Donor blood type O, Recipient blood type A) can match with 9 other pairs, because a blood type O donor can donate to almost any recipient. On the other hand, the recipient in Pair 13 (Donor blood type B, Recipient blood type A) has the same blood type as the recipient in Pair 4, but far fewer match opportunities because of a less-universal donor.
Effect of Travel Preference
Pair 11 (Donor blood type A, Recipient blood type O) can match with 3 other pairs. However, Pair 16 (Donor blood type A, Recipient blood type O) has the exact same blood types for both donor and recipient, but the patients in Pair 16 are unwilling to travel outside of their region and therefore have fewer match opportunities.
Note how many match opportunities exist before Pair 4 and Pair 17 are matched.
Many match opportunities are lost after this one strategically wrong match.
Effect of Each Match
To demonstrate that even one match can significantly affect opportunities for everyone else in the pool, we demonstrate what happens when Pair 4 matches with Pair 17.