A British woman has astounded doctors with a 100-year-old kidney that is still going strong - and thought to be the world’s oldest successfully transplanted organ, reports Daily Mail.

Sue Westhead was in her twenties when she received the organ from her mother, who was 57 at the time, after being diagnosed with kidney disease in 1973.

It was estimated to function for no more than two decades before needing a replacement – but the 68-year-old from Wearside has defied medical expectations with it lasting more than double that.

Mrs Westhead admitted she would have been happy with five years use at the time of the operation, when her skin was yellow and she could barely walk.

Her mother Ann donated her kidney at Newcastle’s Royal Victoria Infirmary after her daughter was told she had the equivalent of a tenth of her kidney function.

Doctors told the family the transplanted organ from a living donor can only last a maximum of 20 years before a further transplant is required - but forty-three years later it is still going strong.

She puts the medical miracle down to looking after herself - and rigorously taking nearly 20 pills a day to make sure her donated organ isn’t rejected.

Upon hearing that she might have the oldest surviving transplanted kidney in the world, she told BBC Newcastle: ‘It’s absolutely mind-blowing. Every superlative you can think of.’ 

According to BBC Newcastle, no one at the British Transplantation Society, the Human Tissue Authority, NHS Blood and Transplant, Kidney Research UK, knows of any other person in the UK who has a transplanted kidney that’s more than 100 years-old.

Professor Derek Manas, president of the British Transplantation Society, said: ‘It’s an amazing story of encouragement and hope for people on dialysis and for encouraging people to donate as living donors or to join the Organ Donor Register. I think Sue must be one of the longest survivors.’

However, it is impossible to verify whether Mrs Westhead has the oldest living transplanted kidney in the world due to the limited recorded data.

In February, the world’s longest surviving heart transplant patient died 33 years after his life-saving operation.

John McCafferty was officially recognised by Guinness World Records in 2013 after his life-saving transplant at Harefield Hospital in west London on October 20, 1982.

Despite being told it would only add five years to his life, he went on to live for more than three decades with the new heart until he died of sepsis and renal failure aged 73.

Last year, around 3000 kidney transplants were carried out in the UK – but there remained more than 5000 people on the waiting list.

The main role of kidneys is to filter waste from the blood and to convert them to urine – but if they lose the ability, waste builds up and can be life-threatening.

On average, the waiting time for a deceased donor kidney transplant is two to three years – but as we have two in our body it is possible to have living donors.