To the man who saved my sister's life: Thank you.

Five years ago, on the 28th of January, we stood as a family in a stuffy hospital room. We crammed around my sister who sat up in bed, after a day of intense testing, ready to eat some lasagna.

The air in the room was humid. But heavier was the news that was about to come, and jolted us from post-Australia day celebrations.

“Samantha, you have Acute Lymphoblastic Leukaemia. If you don’t start treatment immediately you have three months to live. You will never have children.”

The words punctured us, and hung about in the room. Immediately, she started treatment- chemotherapy. Immediately, the doctors began the search for a bone marrow transplant. If chemo didn’t work, she would need a transplant to survive.

Thirty-three per cent of bone marrow transplants are sibling-related. My brother and I were not a match.

Six months on, my sister had lost her hair, her skin had become sallow, her eyes were tired, her eyebrows were gone. Six months on, after tests, MRIs and lumber-punctures, and blood transfusions, and chemotherapy, an MDR said that she was in the High Risk Category, which meant the risk of relapse was greater. The need for a donor became urgent.

In Australia, eight people every day are diagnosed with Leukaemia or a similar blood-related illness. Of those people, 67 per cent of them who require a bone marrow transplant will need to look on the Australian, or global registry.

The waiting seemed endless. Yet on the 3rd of September, just days before my birthday, my sister received a gift from a stranger. A tiny packet of blood was sent from the US. It was her bone marrow transplant. It was to be given as a transfusion.

This older Caucasian man, who was Sam’s match, sent his blood with a card. He said that his wife’s friend had been diagnosed with Leukaemia years ago. He and his friends decided to go on the registry. He was delighted to be a match.

That man saved my sister’s life.

We were among the lucky ones. Of the donors on the worldwide registry, 85 per cent are Caucasian. Sam’s match took eight months to find, and it felt like a lifetime. It easily could have cost us that.

One in 1000 donors on the registry will be a match for the patient needing a transplant. Fifteen per cent of people on the registry are from non-European or mixed ethnic backgrounds, and the search for a match for them is even direr. As the Leukaemia Foundation explains, “Because a person’s tissue type is directly related to his or her ethnic origin, Australia needs donors who reflect many different communities. Without this it becomes difficult to find matched donors of non-European or mixed ethnic backgrounds.”

Shula Endrey-Walder OAM is a genetic scientist who has been taking tissue types and blood samples on a Sunday mornings at the Walper Jewish Hospital since 1994. She set up the program Gift of Life she said, because she “found out that there were very few unrelated donors for minority ethnic groups on the international bone marrow registry.”

She also takes tissue types for Caucasian people who cannot give their blood at the Red Cross or ABMDR because of having lived in the UK between 1980 and 1996.

There are many myths about bone marrow donation that may lead to people not signing up to the registry. For example, Will Smith’s Seven Pounds portrays a bone marrow transplant as a lumbar puncture through the spine. In reality, only one out of 10 bone marrow donations are taken from the hip. Nine out of 10 donations are done through a periphery, through the blood in your arm.

Signing up for the registry is the easiest thing to do. In Australia, it costs nothing. Anyone between the ages of 18 and 40 can join the Australian Bone Marrow Registry. Indicating your ethnicity increases the chance of finding a match.

Signing up for the registry means that you may not ever be called on for a transplant.

Signing up for the registry also means that you may be called on to save a life.

I remember so clearly the day Sam was released from hospital after her bone marrow transplant. We went to a restaurant near the hospital to celebrate the month of September, which marked my birthday, my brother’s birthday and (with her new DNA) my sister’s birthday.

Sam was bloated from neck to toe. Her eyes were puffy. She had baby thin hair, and she walked so slowly, one foot in front of the other, to the restaurant.

In the loud and stuffy Italian restaurant that night, it was difficult not to think of those touch-and-go moments in ICU. That night, words cannot describe how happy we were to have her with us. And that night, I think she even finished her lasagna.

Five years on, my sister still suffers the side effects of graft-versus-host-disease. But five years on, she is also married, has finished her uni degree, and starts teaching in a new job this year.

Five years on, we are so thankful for the gift of life that came in a tiny packed from a stranger in the US that day in September.

To hear more about this story, listen to Clare Froggatt’s TED talk.

To join the bone marrow registry, please sign up to the ABMDR’s website.

If you spent time in the UK from 1980 to 1996, visit the Walper Jewish Hospital and register with Gift of Life.

Emma Froggatt is a Freelance writer, and has been an intern at Mamamia. You can follow her on twitter here.