By Karen Allen
BBC News health correspondent
Scientists are launching a study to determine why transplanted kidneys sometimes fail.
Some organs fail to last
Some 3,000 patients will be monitored as part of the STEPP project to be run by the National Kidney Research Fund.
The aim is to discover why some patients need multiple transplants and others can benefit from their "new" kidney for several decades.
It is hoped the results will enable doctors to refine treatment, and make donated kidneys last longer.
This is particularly important as donor organs are always in short supply.
There is no doubting that organ transplants save lives, but the average lifespan of a transplanted kidney is between 11 and 14 years.
This means some patients will need repeat operations or will return to dialysis.
The National Kidney Research Fund team, working with commercial partners, will study patients from Britain's top five transplant centres.
They hope to understand why in the long term some patients develop high blood pressure and heart disease.
They also want to learn more about whether this is a consequence of the transplant, the anti-rejection drugs that are part of the treatment, or the prolonged dialysis that many patients must endure.
Among those taking part in the study is Riminder Dosanjh, 27, who had her first transplant at the age of five. Just 14 years later the kidney failed.
She has had another transplant - but already there are warning signs that the donated organ may be starting to fail.
"Every patient who does receive an organ thinks that's it for life but that's not the fact," she said.
"I know it's a cruel thing to say but kidney's don't last forever."
For every one patient that receives a donated organ there are five others on the waiting list, and demand for transplants is expected to rise by 7% year on year.
Dr Anthony Warrens, from the National Kidney Research Fund, said anti-rejection drugs are associated with health problems - but understanding the bigger long-term picture could save lives.
He said: "We are hoping to understand better the factors that we will have to correct and intervene with in order to prolong the life of the kidney and therefore prolong the life of the patient.
"And secondly we are hoping that this will increase awareness of the problem and the dire shortage of organs that we have got."
Efforts are already underway to try to boost the numbers on the donor register.
But if transplanted kidneys can function longer that pressure might be eased.
If you would like to register your wishes to become an organ donor, please contact the Organ Donor Line on 0845 60 60 400