SINGAPORE - In 2006, Ms Yow Enning signed up as a bone marrow donor at a school drive.

The process was simple - she gave a blood sample and signed a form with her contact details.

Last year a suitable recipient turned up. It was 29-year-old Indonesian Ivan Wijaya, who had come to Singapore to seek treatment for leukaemia.

Ms Yow did not know him back then. But she could not turn down an opportunity to save a life.

"I felt as if I had struck the charity lottery," she said.

Bone marrow contains stem cells and it is these cells patients need.

Ms Yow went for another blood test to confirm the match. Then she had several injections to stimulate stem cell production in her bone marrow. Finally, she sat hooked up to a machine for six hours to donate the stem cells.

"It was relatively painless and I played computer games," said the 28-year-old.

On Friday, she met Mr Wijaya for the first time.

"You are the reason I am standing here today," he said, hugging her.

"I can't thank you enough for saving my life."

Mr Wijaya was still incredulous over his luck - bone marrow matches are extremely rare - one in 20,000 in one's own racial group.

"Miracles do come true," he said.

This year, Singapore bone marrow donors have helped save 19 people internationally and locally. There are 48,000 donors in the registry, but because matches are so rare, the figure is hardly enough to deal with the 50 international and local requests the Bone Marrow Donor Programme (BMDP)receives each month, said its President Jane Prior.

There are barriers to getting more sign-ups.

Some think that bone marrow donation involves sticking a needle in one's spine, although this is not the case.

In some cases, doctors might use a needle to extract bone marrow from the pelvic bone while the donor is under general anaesthesia, but only one in ten donations are done this way these days, Ms Prior said.

Signing up as a donor these days no longer involves a prick of the finger. It only calls for swabbing the inner part of the cheek, filling in a consent form, then mailing these to BMDP.

Said Ms Yow: "I guess not everyone will be rich enough to donate to charity.

"But by taking five minutes to sign up as a bone marrow donor, you open yourself up to saving someone else's life. It's one of the best decisions I made so far."

Details on bone marrow donation are available at www.bmdp.org.