Living donor requirements
Who can donate a kidney?
Most healthy adults 18 and older can be considered as a living kidney donor. Every center sets its own rules and looks at each person individually, so the only way to know for sure is a free screening. Here is what they generally look at.
Age
The minimum is 18 at most centers, and some prefer donors to be a few years older. There is no official upper age limit. People in their 60s and even 70s do donate. In 2024, about 7 percent of U.S. living kidney donors were over 65.
Weight and BMI
A BMI over 35 usually rules a donor out, because it raises the risk of surgery and of kidney problems later. Between 30 and 35, many centers will work with you and may ask you to lose some weight first.
Blood pressure, diabetes and other health
- Blood pressure: it must be well controlled. Some centers accept donors whose blood pressure is controlled on one or two medicines, especially older donors. Uncontrolled high blood pressure rules you out.
- Diabetes: generally rules you out, because it can damage the kidney you keep.
- Cancer, heart disease, kidney disease: current or serious history usually rules you out.
- Smoking and nicotine: most centers ask you to quit before surgery.
- Kidney stones: a history means extra testing, not always a no.
If you are told no, it is not a rejection of you. It means donating would carry too much risk to your own health. Ask why, and ask whether anything could change the answer.
Do you have to match? Blood type basics
For a direct donation, blood types need to be compatible:
- Type O can donate to O, A, B and AB.
- Type A can donate to A and AB.
- Type B can donate to B and AB.
- Type AB can donate to AB.
Here is the good news: you do not have to match the person you want to help. Through paired kidney donation, your kidney goes to a stranger who matches you, and a stranger's kidney goes to your person. That is exactly how John Watkins is searching for his kidney.
Do you have to be related?
No. Friends, coworkers, church members and even strangers donate every day. Modern anti-rejection medicine makes unrelated donation work very well.
Your mind matters too
Every donor meets a social worker and an independent living donor advocate whose only job is to protect you. You must be choosing freely, without pressure or payment, and you can back out at any time, for any reason. The center will simply say you are not a candidate, without giving the recipient your reason.
Common questions
Who can be a living kidney donor?
Most healthy adults 18 and older can be considered. Centers look at age, weight, blood pressure, kidney function and overall health, and every donor is evaluated individually.
Is there an age limit to donate a kidney?
The minimum is usually 18. There is no official upper age limit, and people over 65 do donate after a careful evaluation.
What BMI is too high to donate a kidney?
A BMI over 35 usually rules a donor out. Between 30 and 35, many centers will consider you and may ask you to lose some weight first.
Can I donate a kidney if my blood type does not match?
Yes, through paired kidney donation. Your kidney goes to a stranger who matches you, and your intended recipient gets a compatible kidney from another donor.
Can I change my mind about donating?
Yes, at any point, for any reason. The transplant center protects your privacy and will not tell the recipient why.
One man in Tulsa is waiting right now.
John Watkins is a dad, a husband and an assistant principal who needs a kidney. Anyone in the U.S. can start the free, private screening for him. You can stop at any step.
Start the screening for JohnKeep reading