Kidney transplantation · Who can receive
Told you are too old, too heavy, or that your first transplant was your only chance?
These are three of the most common reasons patients are turned away. Only one of them is ever a firm line — and even that one can usually be moved.
The short answer
- Age: most transplant centres set no upper age limit. Over 70, the tests are more thorough — but age alone does not rule you out.
- Weight: a body mass index (BMI) of 40 or above is the line. The target is below 30, and patients are helped to get there.
- Being too thin matters too. A BMI below 20 is linked to infection and slower wound healing.
- Second transplant: a failed first kidney is not the end. If it lasted more than four years, the second has an 84% chance of working at three years.
"You are too old for a transplant"
Most transplant centres do not set a fixed age limit. Patients are judged on their suitability for transplantation, not on their birth year.
What does change after 70 is how carefully the team looks. This is not because doctors think a kidney given to an older patient is "wasted". There are two real reasons:
- An older body may have more difficulty tolerating the operation itself.
- The medicines that stop the body rejecting the new kidney can be heavier to carry at that age.
Infections are somewhat more common. But rejection attacks are less frequent and less severe than in younger patients — an older immune system fights the new kidney less.
The transplanted kidney lasts about as long as it does in younger recipients. And five-year survival is higher than for people of the same age who stay on dialysis.
Many teams now match kidneys from older donors to older recipients — a practical way to give more patients in this age group a transplant.
So what actually decides it?
Your heart, lungs and blood vessels — not your age. Every candidate over 50 is screened for heart disease and for cancer before transplantation. If those tests are acceptable, being 72 is not in itself a reason to say no.
"You weigh too much" — and "you weigh too little"
Weight is the one area where there is a firm threshold. International guidelines state that kidney transplantation is not appropriate at a BMI of 40 kg/m² or more.
The reason is not cosmetic. Obese recipients carry a higher risk of heart and blood vessel disease and of surgical complications, and both the patient and the kidney do less well over the long term — mainly for cardiovascular reasons, and secondly because of infection.
| BMI | What it means for transplantation |
|---|---|
| Below 20 | Higher risk of infection and delayed wound healing; shorter life expectancy on dialysis and after transplant |
| 20 – 30 | The target range |
| 30 – 40 | Transplantation possible; weight-loss support recommended |
| 40 or above | Not appropriate — weight must come down first |
A BMI above 40 is a "not yet", not a "never". Patients on the waiting list are given diet programmes and encouraged towards a BMI below 30. After transplantation in heavier patients, the team may also reduce or stop cortisone-type medicines sooner, because these drive weight gain.
The same applies in the other direction. Extreme thinness is a real risk that is talked about far less. A patient who is underweight should be helped to gain weight before surgery.
"Your first transplant failed — there is nothing more we can do"
This is heard more and more often, simply because more people received a first kidney ten or twenty years ago. In the United States, loss of a transplanted kidney is the fifth most common reason for starting dialysis.
A second transplant is not only possible — for these patients it is the best treatment available. Patients whose transplant has failed do worse on dialysis than other dialysis patients, and the ideal is to receive the second kidney before returning to dialysis at all.
What predicts success the second time
| How the first kidney was lost | Outlook for the second |
|---|---|
| First kidney worked for more than 4 years | 84% of second kidneys still working at 3 years |
| First kidney lost within 46 days | About 40% of second kidneys still working at 5 years |
Two further factors matter:
- Why the first kidney failed. If it was lost to an early rejection attack, or because the original kidney disease came back, the team plans the second transplant differently — including the choice between a living and a deceased donor. In other cases, a living donor is preferred.
- Time on dialysis between the two. The longer the gap, the higher the risk. Patients with five years or more on dialysis between transplants carry the greatest risk — another reason not to wait.
My original disease came back in the first kidney. Is a second one pointless?
No. Guidelines state that a repeat transplant should be considered even when the first kidney was lost to recurrence of the original disease. In rare cases the risk of recurrence can be high, but how fast it progresses cannot be predicted — and it is not a reason to refuse outright.
"There is an age limit for kidney transplantation."
At most centres there is not. Advanced age is formally listed as not a contraindication. If you have been refused on age alone, ask what the actual medical reason is — and get a second opinion.
Prof. Dr. Murat Tuncer
Nephrologist and transplant physician. Author of Kidney Transplantation — With Questions and Answers (Istanbul, 2020).
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Tell us your age, your BMI and — if you have had a transplant before — how long it worked. We will tell you honestly whether a transplant is realistic, including when the answer is no.
Medical disclaimer. This article is general information adapted from a published book. It is not personal medical advice, it does not establish a doctor–patient relationship, and it cannot replace assessment by the physician treating you. Eligibility for transplantation is decided by a transplant team after detailed testing. Always consult a transplant centre before making decisions about your treatment.
References
- Abramowicz D, Cochat P, Claas FH, et al. European Renal Best Practice Guideline on kidney donor and recipient evaluation and perioperative care. Nephrol Dial Transplant 2015;30(11):1790–1797.
- Chadban SJ, Ahn C, Axelrod DA, et al. KDIGO Clinical Practice Guideline on the Evaluation and Management of Candidates for Kidney Transplantation. Transplantation 2020;104(4S1):S11–S103.
