KANSAS CITY (AP) - In all but one important way, Jessica McCafferty is a typical 13-year-old. She likes to spend time with her friends, ride her bike, talk on the phone.

But Jessica hasn’t been able to do those things until recently. A kidney disease that has afflicted her since she was 2 years old left her too tired and in too much pain to do much but sit on the couch.

All that changed in March, when Jessica began doing her dialysis at home. While a small but growing number of doctors are encouraging adult patients to try home hemodialysis, Jessica is one of the first children in the United States to try the new treatment.

Dialysis becomes necessary when the kidneys become so weak that they can no longer filter waste and excess fluid from the blood. Now most of the 400,000 Americans with kidney disease are required to spend four hours, three times a week, hooked up to machines at hospitals or dialysis centers.

Proponents believe the home dialysis machines will improve patients’ health because it will clean the blood six times a week, rather than three, and will reduce the high risk of infections faced by dialysis patients.

Most home dialysis done by adults is peritoneal dialysis, which uses the lining of a patient’s abdomen to filter out waste. But the procedure is complicated enough that few patients were able to do it.

The current home dialysis movement is for those using hemodialysis, in which a machine takes in a person’s blood, cleans it, and returns it to the body.

Jessica is doing her dialysis at home six days a week, usually in the morning, for two to three hours. She’s using the NxStage System One, a portable machine about the size of a small television.

High blood pressure is a frequent problem for dialysis patients, and Jessica was taking four medicines twice a day before the home hemodialysis. Now, she’s not on any medicine.

The change has transformed her life, Jessica and her mother say.

"I’m even able to stay overnight with friends," Jessica said. "Before I was pretty much just sleeping and not moving."

The improved health and social life experienced by Jessica and others using home hemodialysis comes mostly from cleaning the kidneys every day, rather than three times a week, doctors say.

"She is a whole new person," said Jessica’s mother, Candace McCafferty. "She has not felt this good for many, many years."

In the past, some adults did home hemodialysis, but it required a machine about the size of a refrigerator and changes to most homes’ water and electrical systems. The smaller machine plugs into a home’s electrical system, does not require special plumbing and is portable.

"We all believe that the current approach to hemodialysis may not be optimal for all patients," said Bradley Warady, Jessica’s doctor, who is director of dialysis and transplantation at Children’s Mercy Hospital in Kansas City.

Children’s Mercy and Texas Children’s Hospital in Houston are testing children on home hemodialysis for the next several months. Texas Children has enrolled its first child, whose family is training to use the machine at the hospital before taking it home, said Stuart Goldstein, director of renal dialysis at the hospital.

"I personally believe home dialysis will be the dialysis of choice in the future," Goldstein said. "Our whole goal is to get transplants for patients, but if we can’t offer that, we are very interested in this technique."

Both doctors stressed that the research is not to test the NxStage, which was given FDA approval last month, but to watch the effect of daily dialysis on children. Besides other benefits, the doctors hope daily dialysis will help reduce inflammations that often plague kidney dialysis patients.

The largest barrier to home hemodialysis is finding children who have caregivers willing to spend weeks learning how to run the machine and who are then able to do it nearly every day at home.

"This is the only disease in children where we ask parents to provide a lifesaving therapy to their children every day, to do it right and not get the kids infected," Goldstein said. "It’s not just giving medicines and monitoring diets. We really have to be careful whom we select."

Jessica was chosen by Warady in part because of her home support. Her mother is the main caregiver, with her father and older brother trained to respond in emergencies.

McCafferty spent about two months training to use the machine at the hospital before the family brought it home in March.

The machine has several alarms to alert her if it’s not set up properly or something goes wrong. She has about two minutes to return her daughter’s blood to her body, or it won’t be usable.

"You have to sort of get over the idea of ‘Oh my God, I’m taking the blood out of her body,’ " McCafferty said. "Technically it isn’t that difficult. It does take training and concentration, but it is not overwhelming."

While her husband works during the week, McCafferty had to quit her day job and works weekends.

"It puts a lot of pressure on the parents," she said. "I told the doctor that he has to warn people that it will take over their lives."

Burnout likely will be the major barrier to more people using the home hemodialysis machine, Warady said. But the hope is that most children would get a transplant before caregivers become overwhelmed.

Despite that concern, the doctors and the McCafferty family recommend the treatment without hesitation.

"The unexpected advantage has been how much better she feels overall," McCafferty said. "We expected her to stable out quite a bit, but we did not expect her to ever be off blood pressure medicine. I would most definitely recommend it."

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