 Kidney exchange. Sometimes potential live kidney donors cannot donate to the recipients they wish because their kidneys are incompatible with the recipient’s body. Many systems now arrange complicated swaps whereby pairs or more than pairs of live donors give to each other’s recipients (Fortin 2013). Sometimes people donate into the general pool in exchange for their preferred recipient getting the next available deceased donor kidney. Unless the preferred recipients would happen to get the deceased donor organ anyway under normal allocation rules, they jump the queue. As with more common methods of live donation, the normal allocation principles are suspended so as not to forgo extra organs.