Blackley, 32, has offered to donate her kidney to Wall, 27, who has a kidney disease.

The transplant, scheduled for Tuesday at UNC Hospitals, is another chapter in Wall's 15-month saga.

In February 2009, he went to the hospital with back pains, but no symptoms of kidney disease. Doctors found that ulcers were causing the pain, but also tested his kidneys.

They found low creatinine levels in his blood. And learned that Wall's kidneys were half the size they should be, and scarred so badly they can't properly filter blood.

Michael says, of the more than dozen others in the dialysis clinic each week, he's the youngest by at least 20 years.

"They said I had the kidneys of an 80-year-old," Wall said. "It was very sudden."

The immediate sacrifices for Wall were changing to a diet without wheat products, dairy products or potassium, and beginning a regimen of dialysis. Three days a week, Wall, an Apex High School alumnus, wakes up at dawn and drives to a dialysis clinic close to his Raleigh home, then to Durham to work the late shift as a deli manager, returning home close to midnight.

"When I go to work on those days, I feel light-headed and weary," he said.

Hopefully for Wall, those days will be drawing to a close.

Next week, Wall and Blackley, who also went to Apex, will don their gowns and begin making what could be a life saving trade for Wall.

Wall's mother, Joy Wall of Cary, and brother were both tested to be donors but were not good matches.

"I was the last eligible family member," said Blackley, who works for the Greater Raleigh Chamber of Commerce.

"It just felt like the right thing to do," she said. Blackley said her decision was easier once she learned that, for her, there is no particular danger to her other kidney.

Her donated kidney, about the size of a fist, will be sewn into place above Michael's right leg, beneath his abdominal wall. It will be attached to blood vessels in the leg and to his bladder.

As thankful as Wall is for Blackley's sacrifice, he realizes this kidney donation is, on one level, just a doorway to a lifetime of challenges.

While waiting in the examination room at UNC Hospitals for his pre-operation appointment on Monday, Wall looked healthy, except for his bruised, swollen and scarred left arm, the one he uses three days a week as the primary outlet and inlet for dialysis.

He was very upbeat while asking questions about the surgery. He was excited to hear that, if things go well, he might be allowed to have sodas and peanut butter sandwiches again. And he joked about being more scared of the urinary catheterization than the kidney transplant.

"I've got the easy job," Wall said.

Nurse Ann Litts agreed.

"Heather will be the one who feels like she's been hit by a truck," she said. "Her surgery is more invasive, and her body won't understand anything about that consent form she signed."

Litts also said she can't remember anyone ever regretting making a donation.

Especially Heather. "She's been just about throwing that kidney at us for months now," said Litts.

Wall's wife, Jaclyn Wall, sat next to him in the examination room. She took notes and worried about the family's finances. "This has put everything on hold," she said.

Michael Wall won't be able to work for three to six months after the surgery. Anti-rejection medication could cost $300 per month out of pocket. The Walls were looking to buy a new home before he was diagnosed, but she says they'll be renting their house from her mother for the foreseeable future.

Michael Wall had other concerns. "I worry about my body rejecting the new kidney, having to go back to dialysis, finding a new donor," he said. "Basically, I worry about all the uncertainty. I also worry how much of a life I might have in front of me. ... This is never going to be over."

On Monday, he and Blackley saw each other only in passing at the pre-operation appointment.

They'll likely see each other even less on Tuesday. They will arrive at 6 a.m. and will be placed in separate rooms. Michael won't be put under anesthesia until doctors are certain things are going well with Heather's procedure.

Her kidney will then be carried, on ice, a few yards to an adjacent operating room where Michael will receive it.