A solid organ transplant is a surgical procedure that replaces a failing organ with a healthy one from a donor. The organs involved are the kidney, liver, heart, and lung, though the pancreas and intestine are also transplanted less frequently. It remains one of the only treatments for end-stage organ failure, and over 48,000 transplants were performed in the United States in 2024 alone.
Which Organs Are Transplanted
The term “solid organ” distinguishes these transplants from tissue transplants (like corneas or skin grafts) and from bone marrow or stem cell transplants, which work differently. The four most common solid organ transplants are kidney, liver, heart, and lung. Kidneys account for the largest share by far, followed by livers. Pancreas and intestinal transplants are less common but use the same basic principles.
Some patients need more than one organ. A person with polycystic kidney disease, for example, may eventually need both a kidney and a liver transplant as the disease progresses. Multi-organ transplants are more complex but follow the same general process of evaluation, matching, surgery, and lifelong follow-up care.
Living vs. Deceased Donation
Organs come from two sources: living donors and deceased donors. Living donation is possible for kidneys (you can live with one) and for portions of the liver, which regenerates. A living donor liver transplant uses the right lobe, left lobe, or a smaller segment, and both the donor’s remaining liver and the transplanted piece grow back toward full size.
Living donation has real advantages. The surgery can be scheduled electively rather than on emergency timelines, the organ spends less time outside the body, and patients on the waiting list face lower risk of dying before a match becomes available. In acute liver failure, where hours matter, having a living donor can be the difference between life and death. The tradeoff is that surgery on a healthy person carries risk. Donor mortality for living liver donation ranges from 0.3% to 1%.
Deceased donation occurs after a person has died, typically from brain death or cardiac death. Most transplanted organs come from deceased donors. In some cases, donor organs carry infections like hepatitis C that require the recipient to undergo additional treatment after surgery.
How Patients Get on the Waiting List
Getting listed for a transplant involves a thorough evaluation that goes well beyond the organ that’s failing. Transplant programs assess both medical and non-medical factors. On the medical side, the team looks at life expectancy, the likelihood that a transplant will provide meaningful years of life, and whether the patient can survive the surgery itself.
Non-medical factors play a significant role too. Programs evaluate psychosocial readiness: whether you have a support network to help with transportation, medication management, and symptom monitoring after surgery. Adherence history matters, meaning whether you’ve been able to follow medical recommendations in the past. Substance use is considered, though programs increasingly view it through a treatment lens rather than as an automatic disqualifier. Notably, immigration status cannot be used to deny someone a transplant, and age alone is not supposed to be a barrier.
How Organs Are Matched and Prioritized
Once listed, patients don’t simply wait in line. Each organ type has its own scoring system that ranks candidates based on medical urgency, compatibility, and expected outcomes.
- Kidney: Allocation uses a combination of scores that assess both the donor kidney’s quality and the recipient’s expected survival after transplant. Factors include the patient’s age, diabetes status, time on dialysis, and immune compatibility.
- Liver: The MELD score (Model for End-Stage Liver Disease) ranks patients by how sick they are right now, using blood tests that measure liver and kidney function. Higher scores mean greater urgency.
- Lung: The Lung Allocation Score balances how urgently someone needs a transplant against how likely they are to survive afterward. It incorporates breathing capacity, oxygen needs, walking ability, and dozens of other variables.
- Heart: A six-tier system stratifies patients by the intensity of medical support keeping them alive, from mechanical circulatory devices at the top tier to stable conditions like certain cardiomyopathies in lower tiers.
Currently, more than 103,000 people are on the national transplant waiting list. The gap between available organs and people who need them remains the central challenge in transplant medicine.
What Happens After Surgery
The surgery itself varies by organ but typically requires a hospital stay of days to weeks, followed by months of recovery. What makes organ transplantation unique compared to other surgeries is what comes after: a lifelong commitment to anti-rejection medications.
Your immune system treats a transplanted organ as foreign and will attack it without medication to suppress that response. These drugs are effective, but they come with significant long-term side effects, including higher risk of infections (because the immune system is intentionally weakened), increased risk of certain cancers, diabetes, high blood pressure, high cholesterol, and stomach problems. Managing these side effects becomes a permanent part of life after transplant.
Rejection and Long-Term Risks
Even with medication, rejection can happen. Acute rejection is most common in the first year, driven by the immune system mounting either a cell-based or antibody-based attack against the donor organ. It can range from completely silent, detectable only through biopsies or lab tests, to obvious symptoms like fever, cough, shortness of breath, or declining organ function. When caught early, acute rejection is often treatable with adjustments to medication.
Chronic rejection is a slower, more insidious process that develops over years. It involves gradual scarring and deterioration of the transplanted organ, often without a single identifiable cause. Repeated low-grade rejection episodes, infections, and other stressors compound over time. Chronic rejection is harder to reverse and is a leading cause of organ loss in the long term.
Complicating matters, infection and rejection can look identical from the outside, sharing the same symptoms or sometimes producing no symptoms at all. This is why transplant recipients follow strict schedules of blood work, biopsies, and clinic visits, especially in the first year.
Survival Rates
Outcomes vary by organ, but overall survival has improved steadily over the decades. For lung transplants, which historically have the lowest survival among the major organs, about 85% of recipients survive to one year, 67% to three years, and 54% to five years. Kidney and liver transplants generally have higher survival rates, with many recipients living 15 to 20 years or more with a functioning graft. Heart transplant outcomes fall between these ranges.
Beyond survival numbers, quality of life improves dramatically for most recipients. People return to work, raise families, and live actively in ways that end-stage organ failure made impossible.
Pig-to-Human Transplants on the Horizon
The organ shortage has driven research into xenotransplantation, the transplanting of organs from genetically modified pigs into humans. Starting in 2022, pig kidneys were transplanted into brain-dead individuals to study feasibility. In March 2024, the first living patient received a pig kidney. The kidney functioned well initially, but the patient died about two months later from causes apparently unrelated to the transplant. The longest a patient has survived with a pig kidney is 130 days.
In early 2025, the FDA approved two clinical trials for pig kidney transplants. One plans to enroll up to 50 patients with end-stage kidney disease, with outcomes measured over 24 weeks. A second study is transplanting pig kidneys into three patients under a compassionate use protocol. The donor pigs have been genetically engineered to reduce the risk of transmitting pig viruses to humans, though whether that strategy works long-term remains an open question. Clinical success is far from guaranteed, but these trials represent the most concrete steps yet toward an alternative organ supply.