SAN DIEGO, Calif. (CBS 8) - San Diego's first three-way kidney transplant is almost finished. A woman will go under the knife Wednesday to receive a kidney from a mystery donor.

The surgery is in the final leg in a complicated triple operation that's connecting multiple strangers to increase the chances of finding a match.

We asked doctor Randy Schaffer what kind of person decides to donate a kidney to a complete stranger.

"An amazing one, to begin with," Dr. Schaffer said.

That San Diego woman donated her kidney to a woman she didn't now, whose husband then donated a kidney to a stepfather whose stepdaughter then donated her kidney to a San Diego student.

"It's always pressure when you're doing something on a person who steps forward voluntarily and says 'Please remove part of my body for someone else,'" Dr. Schaffer said.

All three of the donors are strangers with the recipients. The hospital says it took a year to match blood and antibody types and piece this puzzle together.

Michelle Roberts, director of transplants at La Jolla Green Hospital, says anonymous kidney exchanges are a growing trend in the United States.

"Organ donation and organ availability is so low, so you think you can do this by giving to another and pay it forward, is really going to help people get off the list," Roberts said.

More than 100,000 Americans are currently waiting for organ transplants.

"In San Diego the average wait for a kidney from the deceased donor list is five years," Dr. Schaffer said.

Locating a live donor means an instant lifestyle change, free from dialysis.

"If you are on hemo-dialysis you spend about four hours three times a week sitting in a chair hooked up to a machine doing nothing," Dr. Schaffer said.

It's a holiday gift exchange like no other, started by an altruistic woman who asked for nothing in return.

"This is really about the act of doing something for someone. It's not about gaining publicity, it's not about 15 minutes of fame," Dr. Schaffer said.