Why most kidney exchange chains have patients receive a kidney before their donor donates one

A "how could things go wrong" story from Canada, when a donor donates before her recipient receives a kidney (due to a last minute glitch):
Organ exchange program slow to deliver on promise to man in need of a kidney, family says
Canadian Blood Services says overall, the kidney exchange program has been successful

"A national program that matches living kidney donors with recipients hasn't delivered on a promise after a woman donated a kidney to a stranger so her ailing son-in-law could get a much-needed transplant, the family says.

"Estella Jamieson agreed to donate one of her kidneys, only after being assured her son-in-law would soon get a transplant. She says she decided to contact Go Public because he is still waiting.

"I know I helped somebody and I'm glad that family is going good, but I just feel if I would have waited I could have helped my own family more," a teary Jamieson says. 

"Jamieson and her son-in-law, Jeff Pike, signed up for the Living Kidney Donor Paired Exchange Program a couple of years ago. It's run by Canadian Blood Services along with provincial transplant programs. 

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"Jamieson gave her kidney to a stranger, so Pike could get one from another donor. 

"We did our half. My mother-in-law has helped improve someone's life but the return of her doing that, is someone would in turn help me at the same time — not some time down the road when the stars align. I can't help but feel like there are options out there that could speed things up," Pike says. 

"The surgeries were scheduled for February, but the day before Pike's procedure, he developed shingles and couldn't go through with the transplant. Jamieson donated a kidney anyway, on the promise her son-in-law would get a kidney when his health improved. Pike was medically cleared less than a month later but is still waiting. 

"I was assured Jeff would be top priority if I went through with the surgery. It's seven months later and he still doesn't have a kidney. Even if he had date ... but there's no date, there's nothing," Jamieson says.

"While Pike waits, he can't work full-time and is physically weak. He also requires dialysis twice a day. 

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"Despite all that's happened, Estella Jamieson says she would still recommend the program to others, with one caveat. 

"Don't get me wrong. I think it is a very good program and anyone with a loved one that wants to go into it, I'd say yes to go ahead. But make sure your loved one is getting a kidney when you give yours."