A mother-of-five has become the first Briton to travel to Israel to donate a kidney and save the life of a stranger.
Tzivia Abrams, 40, went back to work as an office administrator on Monday, just over a week after after donating her organ to 10-year-old Hodaya Amran, from Elad.
Because Hodaya's problems were genetic, her own family was unable to help her.
"Their doctors told them - you're Orthodox, go and find yourself a donor," said Ms Abrams, of Stamford Hill.
She considered organ donation when her niece was born with health problems. It was not needed but the idea was there, and when she read about a father-of-eight in America who needed a donor, she contacted Save 1 Person, the campaign group helping him.
When his insurers refused to cover her medical costs, Save 1 Person put her in touch with Hodaya's family in Israel.
After tests in the UK, he flew to Israel where she was questioned by a psychologist and then a panel consisting of a paediatrician, a social worker and a lawyer.
"They wanted to discover whether I was being paid to donate the kidney, so I had to show them bank statements and tell them about my financial position. They asked me why I would donate a kidney to a stranger. That's something I can't even explain to myself. It's not about why - it's about why not?"
She had planned to have the operation just before Pesach, so that her children could join her in Israel for Yomtov, but Hodaya's health deteriorated and she flew out immediately. She says her children were worried about her, but once in Israel she felt "calm and relaxed. It was as though I were going to have a pedicure".
She said: "The operation was so simple. It was keyhole surgery and they glued me back together. By Friday morning I was out of bed. I was able to go over and see Hodaya in the ICU.
"They were scanning her and it was weird to see my kidneys in someone else's body. I was out of hospital and out shopping in under a week, and back to England after six days."
If my children should ever need a kidney, Baruch Hashem, they have each other. There are always excuses, reasons why you should not do something like this. Anyone can make excuses.
But if I can do this, a single mother of five who works full time, then others can. Some people are billionaires, they choose which causes to support. I chose to do this. I feel privileged I was able to."
Hodaya wrote to her this week saying: "Tzivia, I love you and am already missing you. You saved my life. Now I can drink as much as I want and I am allowed to eat whatever I want.
"I don't need dialysis anymore. I don't suffer anymore. I don't need any more big needles. I can play like everyone else. I am back to living a regular life like all my friends. "
Chaya Lipshutz, who runs the American website kidneymitzvah.com, said the regulations surrounding organ donation in the UK to be changed so Jewish people can donate to strangers within the Jewish community. At present people in the UK can only donate to family, friends or strangers picked for them by the NHS.