Most healthy adults aged 18 or older can be considered to donate a kidney while alive, even if they are not related to the person who needs it. They must have healthy kidneys, be well enough for surgery, and freely choose to donate. A transplant team checks their health and whether the kidney is a suitable match. People may also register to donate organs after death.
Who is eligible to donate a kidney while alive?
A living kidney donor is someone who gives one of their two kidneys to a person who needs a transplant. Because one healthy kidney can usually provide enough function to support the body, many carefully selected people can live well after donating the other kidney.
According to the National Kidney Foundation, living donors generally must be at least 18 years old, although some transplant centers set a higher minimum age. They must also be healthy enough to undergo surgery and live safely with one kidney. Exact eligibility rules depend on the country and transplant center.
Potential donors do not need to be related to the person receiving the kidney. The transplant team considers the donor's health, the recipient's needs, and whether the kidney can be transplanted safely.
Does a kidney donor have to be a family member?
No. A suitable kidney may come from a relative, a spouse or partner, a friend, a coworker, or someone who does not personally know the recipient. What matters most is the donor's medical suitability and the possibility of a safe transplant, rather than a family relationship alone.
Living kidney donation generally falls into two categories:
- Directed donation: The donor intends to give a kidney to a specific person, such as a parent, sibling, child, spouse, or friend.
- Non-directed donation: The donor offers a kidney to someone they have not selected personally. The transplant team identifies a suitable recipient according to medical and matching criteria.
Some donors and recipients are medically compatible from the beginning, while others are not. The Mayo Clinic explains that paired kidney donation may help when a willing donor cannot safely donate directly to their intended recipient. In this arrangement, two or more donor-recipient pairs are matched so that each recipient can receive a more suitable kidney.
What health conditions can prevent someone from donating a kidney?
A potential donor must have kidneys that function well and a level of overall health that makes the operation and life afterward acceptably safe. Certain medical conditions can increase the risk of surgery or future health problems with the remaining kidney. Others may require additional investigations before the transplant team can decide whether donation is appropriate.
Conditions and circumstances that may prevent or delay living kidney donation include:
- Existing kidney disease: Reduced kidney function or other evidence of kidney damage can make donation unsafe.
- Diabetes or a high risk of developing diabetes: These may increase concern about future kidney health and can make someone ineligible.
- High blood pressure: Uncontrolled blood pressure or evidence that it has damaged the kidneys may prevent donation. Some people with well-controlled blood pressure may still qualify after further assessment.
- Significant excess weight: Higher body weight can increase surgical and long-term health risks. Some candidates may need additional testing or to lose weight before reconsideration.
- Active cancer or a history of certain cancers: Eligibility depends on the cancer type, treatment history, and risk to the donor and recipient.
- Certain infections or significant heart and other medical conditions: These may make major surgery unsafe or affect the safety of the donated kidney.
- Other factors affecting safe recovery: Some medications, smoking, or alcohol and drug use may require further evaluation or changes before donation can proceed.
The NHS Organ Donation service emphasizes that potential donors are assessed individually, including those with high blood pressure, diabetes risk, higher body weight, or a history of cancer. Having one of these factors does not always produce the same decision for every person. The transplant team considers the full medical history and the results of the donor evaluation.
Is there an upper age limit for kidney donation?
There is no single upper age limit that applies to every living kidney donor program. Many programs require donors to be adults, usually aged 18 or older, but an older person may still be considered if their kidney function and overall health are suitable. Age alone does not establish whether someone can safely donate.
Older potential donors may need careful assessment of kidney function, blood pressure, heart health, and other conditions that can affect surgical risk. The transplant center decides whether the likely risks are acceptable for that individual.
People younger than the required minimum age generally cannot donate a kidney while alive through standard living-donor programs. The legal requirements for consent and donation vary by location, so the applicable transplant program must confirm the rules.
Does a kidney donor need the same blood type as the recipient?
No. A compatible blood type can make transplantation more straightforward, but having different blood types does not automatically mean a transplant is impossible. The transplant team checks blood type, immune-system compatibility, and other factors to estimate the risk of rejection and determine which transplant options may be suitable.
If a donor and recipient are not a suitable match, the team may consider a paired kidney exchange. This allows a donor to give a kidney to another compatible recipient while the original recipient receives a kidney from a different donor. Some centers may also offer other approaches for selected incompatible donor-recipient pairs.
The Health Resources and Services Administration (HRSA) describes kidney paired donation as an option for people who have a willing donor but are not medically compatible. Availability depends on the transplant program and the applicable donation system.
What tests are needed before someone can donate a kidney?
Being willing to donate is the first step; approval follows a thorough medical assessment. The purpose is to confirm that the donor has healthy kidneys, can undergo surgery safely, understands the risks, and is making a voluntary decision.
The evaluation usually includes several of the following steps:
- Medical history and physical examination: The team reviews current and previous illnesses, family history, medications, blood pressure, and general health.
- Blood and urine tests: These assess kidney function and look for signs of kidney damage, diabetes, infection, or other health concerns.
- Blood group and immune compatibility tests: These help determine whether the donor's kidney may be suitable for the intended recipient.
- Imaging tests: Scans examine the kidneys, their structure, and their blood supply to help surgeons plan the operation.
- Additional medical assessments: Depending on the donor's history and test results, the team may arrange heart tests, infection screening, cancer screening, or other investigations.
- Psychological and practical assessment: The team explores the donor's understanding of donation, emotional readiness, support during recovery, and ability to make an informed choice without pressure.
Not every potential donor needs exactly the same tests. The transplant center determines which investigations are necessary and reviews the results before making a decision. A person who is not approved at one center may ask whether another center can review their circumstances, although approval is never guaranteed.
Can someone donate a kidney after death?
Yes. Kidneys can also be donated by someone who has died, provided the circumstances and medical assessment allow organ donation. Unlike living donation, this does not require the person to undergo surgery while alive. Specialist clinicians assess whether the organs are suitable at the time of death.
Age and a history of illness do not automatically rule out deceased organ donation. For example, the NHS Organ Donation service states that there is no age limit for registering a decision to donate kidneys after death, and that suitability is assessed individually. Registration processes, consent requirements, and medical eligibility rules differ between countries.
What should you consider before agreeing to donate a kidney?
Living kidney donation is major surgery, even when the donor is in good health. Before agreeing, a potential donor should understand the recovery process, possible surgical complications, follow-up requirements, and the possible long-term effects of living with one kidney. These may include high blood pressure, protein in the urine, or reduced kidney function. Some studies also suggest a slightly higher future risk of kidney failure among living kidney donors, although the overall risk remains low for carefully selected donors.
The Mayo Clinic's guidance on living donation explains that donor assessment is intended to reduce these risks through detailed testing and informed consent. Donors should have an opportunity to ask questions, discuss personal concerns, and consider how recovery could affect work, family responsibilities, and finances.
Donation must be voluntary. A person should not feel obliged to donate because of family expectations, financial pressure, or concern about disappointing the intended recipient. Potential donors can discuss their decision privately with the transplant team and may change their mind during the evaluation process. The team can explain the next steps and available support without requiring the person to proceed.
How can you find out if you are eligible to donate a kidney?
If you are considering living kidney donation, contact a transplant center or ask your healthcare professional how to reach a living-donor program. The center can explain local requirements and arrange an initial confidential assessment. You do not need to decide on surgery before asking questions or starting an evaluation.
Only the transplant team can determine whether donation is suitable after reviewing your health, kidney function, compatibility results, and individual circumstances. If living donation is not considered safe for you, you may ask the team whether other ways of helping the intended recipient or registering for deceased organ donation are available in your location.