A 25-year-old doctor from Pembrokeshire has given the chance of survival to a patient over 5,000 miles away.

Blood stem cells donated by Charlie Ratcliffe have been flown to South America to be received by a man the same age who has a form of leukaemia.

“I have looked after patients whose last chance of survival is a bone marrow transplant, so I feel privileged to have been able to give this man a chance,” said Dr Ratcliffe, a paediatric doctor at the University Hospital of Wales, Cardiff.

She joined the Welsh bone marrow register at a blood donor session when she was 18 and a pupil at Tenby’s Greenhill School, where she was head girl.

“Giving blood is something I have always felt strongly about, and I had no reservations about signing up,” she said this week. “I then found out in June that I was a potential bone marrow match for the man who has acute lymphoblastic leukaemia.”

Bone marrow creates stem cells, which grow on to become normal blood cells, and 90 per cent of donations are of stem cells, rather than bone marrow.

Following extensive tests and four injections to stimulate her bone marrow growth, Dr Ratcliffe was admitted to a hospital in Newport where she spent 12 hours having blood taken out of one arm, passed through a cell-separating machine and then returned to the other arm.

“I cannot thank the staff at the Welsh Blood Service enough for all of the support they provided before, during and after the procedure,” she said. “The whole process was quite tiring, but I was back to my normal self the following day and even went for a run.”

Dr Ratcliffe is now urging blood donors aged between 18 and 46 to ask to be put on the Welsh Bone Marrow register at their next donation.

“Unfortunately, around 2,000 people - including 300 children - in the UK need a bone marrow transplant each year, and currently a matching donor is only found for half of these,” she explained. “We urgently need more people to join the bone marrow registry, and in particular we need more young men.

“Currently, young men make up only 15 per cent of the register, but are far more likely to be chosen to donate by transplant centres, and provide nearly half of all donations.

People aged between 16 and 30 can also sign up to the register of the Anthony Nolan charity, which is dedicated to saving the lives of patients who need a stem cell transplant.

For more information, visit www.welsh-blood.org.uk and www.anthonynolan.org