Very few medical conditions permanently disqualify someone from organ donation. The list of absolute exclusions is far shorter than most people assume, and it has been shrinking for decades as transplant medicine finds ways to use organs that would once have been discarded. Active infections, certain cancers, and a handful of untreatable transmissible diseases remain genuine barriers, but even many of these are conditional rather than permanent. The gap between public perception and clinical reality is wide enough that it costs lives: people who could save others never register as donors because they wrongly believe a diagnosis rules them out.
The Short List of Near-Absolute Exclusions
Transplant teams evaluate every potential donor individually, so blanket rules are rare. Still, a few conditions come close to universal disqualification. Active, disseminated infection with certain organisms that cannot be cleared from the donated organ is one. Prion diseases, including Creutzfeldt-Jakob disease (CJD) and its variants, sit at the top of that list. The infectious proteins responsible for prion disease cannot be destroyed by standard sterilization, and there is no treatment if transmitted. Any donor undergoing autopsy for evaluation of a possible central nervous system disease of this kind is absolutely excluded.1PubMed. Risk of prion disease transmission from ocular donor tissue transplantation
Active, uncontrolled rabies is another near-universal exclusion, for similar reasons: once established, the virus is essentially untreatable in the recipient. Certain multi-drug-resistant infections that cannot be cleared with available antibiotics also fall into this category, though the specifics depend on which organism is involved and which organ is being considered.
Beyond these, the picture becomes much more nuanced. Most conditions people assume are disqualifying, including HIV, hepatitis C, many cancers, old age, diabetes, and drug use, are either no longer automatic exclusions or were never as restrictive as the public believes.
Cancer in the Donor’s History
A history of cancer is one of the most common reasons people think they cannot donate, and the reality is complicated but far more permissive than expected. The central concern is donor-transmitted cancer (DTC), where malignant cells travel with the organ into an immunosuppressed recipient whose body cannot fight them off. That risk is real but quite small. A large European analysis of more than 32,000 transplant recipients found that confirmed cancer transmission occurred in just four cases, a per-transplant risk of about 0.01%. Even among recipients who specifically received organs from donors with known malignancies, the transmission rate was under 0.3%, and the fatality rate was about 0.14%.2European Journal of Transplantation. Organ transplantation from donors with malignancies: risk assessment and clinical outcomes
The type of cancer matters enormously. Brain tumors are among the most commonly encountered cancers in deceased donors, since brain death can result from malignant brain disease. Fortunately, most primary brain tumors almost never spread outside the skull. A study tracking recipients who received organs from donors with brain tumors found that none of the post-transplant cancers that developed matched the donor’s brain tumor type.3PubMed Central. Organ Transplants From Deceased Donors With Primary Brain Tumors and Risk of Cancer Transmission Korean data on donors with central nervous system tumors reached a similar conclusion: the risk of disease transmission was very low, and the researchers argued that donation from such donors should be actively promoted.4PubMed. Safety of Donation From Brain-dead Organ Donors With Central Nervous System Tumors: Analysis of Transplantation Outcomes in Korea
Other cancer types carry more nuance. Analysis of U.S. transplant data found that donors with a cancer history were an independent risk factor for poorer outcomes in liver and heart transplantation specifically. For liver recipients, five-year survival was modestly lower, and for heart recipients the effect was somewhat larger. Kidney transplants from donors with genitourinary or gastrointestinal cancer histories also showed reduced survival, and heart transplants from donors with hematologic malignancies had notably worse outcomes.5PubMed Central. Outcomes of Organ Transplantation from Donors with a Cancer History These findings do not mean organs from donors with cancer histories are never used. They mean transplant teams weigh the specific cancer type, how long ago it was treated, and whether the recipient’s alternative is continuing to wait on an ever-lengthening list. As donor pools skew older, more donors carry cancer histories, and the transplant community is actively working out which combinations of cancer type and organ type are safe enough to proceed.6PubMed Central. Donors With Previous Malignancy: When Is It Safe to Proceed With Organ Transplantation?
HIV, Hepatitis C, and the Changing Rules Around Viral Infections
For decades, HIV-positive status was an automatic and total barrier to organ donation in the United States. That changed with the HIV Organ Policy Equity (HOPE) Act, signed in 2013, which reversed the federal ban on transplanting organs from HIV-positive donors into HIV-positive recipients.7PubMed Central. The future of HIV Organ Policy Equity Act is now: the state of HIV+ to HIV+ kidney transplantation in the United States Initially, all such transplants had to occur under research protocols with safeguards mandated by the National Institutes of Health.8PubMed Central. Realizing HOPE: The Ethics of Organ Transplantation From HIV-Positive Donors By early 2019, more than 50 HIV-positive donors had provided organs for over 120 transplants, and ongoing studies continue to evaluate safety and outcomes.
The hepatitis C story may be even more transformative. The arrival of direct-acting antiviral drugs (DAAs) that cure hepatitis C in the vast majority of patients has opened a new frontier: transplanting hepatitis-C-positive organs into recipients who do not have hepatitis C, then curing the infection with a short course of antivirals afterward. In an early trial, ten kidney recipients who received organs from hepatitis-C-positive donors and were given antiviral prophylaxis had no detectable virus twelve weeks after treatment, with no treatment-related adverse events.9PubMed Central. Direct-Acting Antiviral Prophylaxis in Kidney Transplantation From Hepatitis C Virus-Infected Donors to Noninfected Recipients: An Open-Label Nonrandomized Trial
Cost-effectiveness modeling reinforces this approach. Accepting a hepatitis-C-positive kidney and treating the infection afterward was projected to produce slightly more years of life at roughly $138,000 over five years, compared to about $329,000 for staying on dialysis while waiting for a hepatitis-C-negative organ.10PubMed. Cost-effectiveness of hepatitis C-positive donor kidney transplantation for hepatitis C-negative recipients with concomitant direct-acting antiviral therapy In practice, access to these antivirals after transplant has been achievable: among 91 patients in one real-world study, all obtained the drugs through prescription insurance or patient assistance programs, though getting insurance approval sometimes required significant administrative effort.11PubMed. Access to hepatitis C direct-acting antiviral therapy in hepatitis C-positive donor to hepatitis C-negative recipient solid-organ transplantation in a real-world setting
The upshot is that HIV and hepatitis C are no longer automatic disqualifiers for donation. They are conditions that restrict which recipients can receive the organs and under what clinical protocols, but they do not remove organs from the pool altogether.
Bacterial Infections and Sepsis
A donor who dies in an intensive care unit after a prolonged stay often has a bacterial infection, sometimes involving the bloodstream. This understandably raises concern, but it does not rule out donation. A single-center study examining 22 liver and 46 kidney transplants from donors with confirmed systemic bacterial infections (positive blood cultures at the time of organ recovery) found that not a single case of bacterial transmission to the recipient occurred when prophylactic antibiotics were used. The researchers concluded that systemic infection in the donor is not a contraindication for organ donation.12PubMed. Organ Donation and Transplantation From Donors With Systemic Infection: A Single-Center Experience The key is identifying the organism, choosing the right antibiotics for the recipient, and monitoring closely in the early post-transplant period.
Age, Chronic Disease, and Expanded Criteria Donors
There is no upper age limit for organ donation. Organs from donors well into their seventies and eighties are used regularly, though older organs tend to function differently than younger ones and are matched accordingly. The transplant field formalized this through the concept of “expanded criteria donors” for kidneys, which includes all donors aged 60 and older, as well as donors aged 50 to 59 who also have at least two of three additional risk factors: death from a stroke, elevated kidney function markers, or a history of high blood pressure.13Transplantation Reviews. The use of expanded criteria donor organs for transplantation These kidneys carry a higher rate of delayed function after transplant, but studies have found no evidence of reduced long-term graft survival compared to standard-criteria donors.14PubMed. Outcome of kidney transplantation from elderly donors after cardiac death
Chronic diseases like diabetes and hypertension, which are common in older donors, do not automatically exclude a person either. They affect how an organ is allocated and to whom. A kidney from a 70-year-old donor with well-controlled hypertension may go to a 65-year-old recipient who would benefit enormously from getting off dialysis, even if that kidney would not be the first choice for a 30-year-old recipient expected to need decades of graft function.
Organ-Specific Reasons for Turning Down a Donation
Even when a donor is medically acceptable in general, individual organs may not be usable. These organ-specific exclusions are worth understanding because they are among the most common reasons a willing donor’s organs are ultimately declined.
For livers, fatty liver disease (hepatic steatosis) is a leading reason for rejection. Given the prevalence of obesity, a large proportion of potential donors have some degree of fat in their livers, and heavily fatty livers perform poorly after transplant. One case report highlighted that a potential living donor lost 86 pounds to resolve severe steatosis before becoming eligible, underscoring both the barrier and the fact that it can sometimes be overcome.15Experimental and Clinical Transplantation. Resolution of Severe Graft Steatosis Before Living-Donor Liver Transplant After 86 Pounds of Weight Loss
For hearts, functional problems detected during evaluation are the usual culprit. A Spanish study of potential heart donors who were ultimately excluded found that thirteen were turned down due to known heart disease or cardiac risk factors, including hypertensive heart disease, long-standing diabetes, and valve disease. Another eleven donors with no known heart problems were excluded after echocardiography or surgical inspection revealed abnormal contraction. In most of those cases, the dysfunction was attributed to changes related to brain death itself rather than underlying cardiac disease, a frustrating situation where a potentially usable heart is lost to a reversible process.16Revista Española de Cardiología. Can Heart Donation Exclusion Factors Be Overcome?
For lungs, a donor’s smoking history is a major consideration. Research using detailed lung function testing found that donor smoking was associated with measurable increases in small-airway resistance in the transplanted lung, suggesting that smoke-damaged airways carry lasting functional deficits even after transplantation.17Frontiers in Medicine. Effects of donor smoking history on early post-transplant lung function measured by oscillometry Lungs from smokers are still used in practice, particularly when the alternative is the recipient continuing to deteriorate on the waiting list, but the known functional trade-off means these organs are allocated with extra caution.
Why Living Donors Get Turned Down
Living donation, most commonly of a kidney or a portion of the liver, has its own set of exclusion criteria that differ from deceased donation. A study at a single U.S. center documented the most common reasons living donor candidates were denied. The top reasons were medical: being too young (under 25), having a first-degree relative with diabetes, having pre-diabetes or diabetes, or having another unspecified medical issue. The leading social reason for denial was a psychiatric history other than depression, and the leading surgical reason was the discovery of a lesion on the kidney during imaging.18PubMed Central. Multiple Reasons for Living Donor Denial: A Single Center Experience
The logic behind these restrictions is different from deceased donation. With a deceased donor, the risk calculation is entirely about the recipient: will this organ help more than it hurts? With a living donor, the transplant team also has to protect the donor from harm. Removing a kidney from someone with early signs of diabetes or kidney trouble could put that person at risk of kidney disease down the road. An age floor exists because very young adults may not yet have fully developed the capacity for the kind of long-term risk evaluation involved. And psychiatric screening exists less as a moral judgment than as a safeguard against coercion or impulsive decisions that the donor may regret.
Drug Overdose Deaths and Donor Utilization
The opioid crisis has reshaped the organ donor pool in the United States. A significant share of deceased donors now die from drug intoxication, and this has raised questions about whether these organs are safe. The data suggests they are, though utilization patterns reveal lingering hesitation. Donors who died from trauma had the highest utilization rate at about 97%, while donors who died from cardiovascular causes had the lowest at around 90%. After adjusting for other factors, brain-dead donors from drug intoxication actually had slightly higher odds of their organs being used compared to trauma donors. Among donors who died after circulatory death, however, drug intoxication donors were used at lower rates than trauma donors.19PubMed Central. Drug Overdose and Cardiovascular Deaths Among Deceased Organ Donors: Implications for Donor Utilization and Data Reporting
The practical takeaway is that a death caused by drug overdose does not disqualify someone from organ donation. The organs themselves are evaluated on their own merits, and in many cases they function as well as organs from donors who died by other means.
Donation Timing and Warm Ischemia
One factor that can turn a willing donor’s organs into unusable ones has nothing to do with the donor’s medical history: it is how long the organs go without blood flow. When donation happens after circulatory death (as opposed to brain death, where the heart is still beating during organ recovery), the clock starts ticking the moment blood stops circulating. This period of “warm ischemia” damages cells progressively.
Research on cardiac donation after circulatory death found that significant cellular damage in heart muscle begins around ten minutes after cardiac arrest, with declining mitochondrial function and rising markers of cell death.20PubMed Central. Critical warm ischemia time point for cardiac donation after circulatory death For kidneys, the picture is more forgiving. A comparison of nearly 3,000 kidney transplants found no significant difference in five-year graft survival between kidneys from donors after circulatory death with longer warm ischemia times (over 60 minutes) and those with shorter times or from brain-dead donors; all three groups had graft survival rates around 83 to 84%.21PubMed. Impact of Warm Ischemia Time on Donation After Circulatory Death Kidney Transplant Outcomes That said, warm ischemia interacts with cold storage time. When kidneys from circulatory death donors also faced long cold storage (24 hours or more), the risk of graft loss climbed, and the effect was worse the longer the initial warm ischemia had been.22PubMed. Donor Warm Ischemia Time Modifies Susceptibility to Cold Ischemia in Donation After Circulatory Death Kidney Allografts Under Hypothermic Machine Perfusion
This means that logistical factors, how quickly a team can recover the organs, how far they need to travel, and how they are preserved, can effectively exclude organs that were perfectly healthy in the donor’s body.
Pediatric and Neonatal Donation
Children and even newborns can be organ donors, though the process involves additional ethical and practical hurdles. Brain death determination in neonates requires longer observation periods than in adults, and diagnosing brain death in very premature infants remains medically uncertain. The U.S. Organ Procurement and Transplantation Network has established specific procedures for pediatric organ allocation that account for donor-specific and recipient-specific factors.23PubMed Central. Neonatal and Pediatric Organ Donation: Ethical Perspectives and Implications for Policy
One area of ongoing ethical discussion involves neonates born with immediately lethal conditions such as anencephaly, where the brain largely fails to develop. These infants will die shortly after birth, and their organs could potentially save other newborns. Donation in such cases has been attempted but remains uncommon and ethically contested, partly because of difficulty establishing brain death using standard criteria in these patients and partly because of concerns about the appearance of treating a dying newborn primarily as an organ source.
Genetic and Metabolic Diseases
If a potential donor has a genetic metabolic disorder, the question is whether the donated organ will function adequately in the recipient or whether it will carry the disease along with it. For recipients who need a transplant because of a metabolic disorder, the answer sometimes involves using organs from carriers. A study of 46 children who received liver grafts from parents who were heterozygous carriers of conditions like Wilson disease, ornithine transcarbamylase deficiency, and several others found that the parental grafts generally functioned well and corrected the metabolic defect, though outcomes were better in diseases where the liver itself is the primary problem rather than diseases where the metabolic defect also affects other organs.24PubMed. Living donor liver transplantation for pediatric patients with inheritable metabolic disorders
Primary mitochondrial diseases represent a trickier category, since these disorders can affect multiple organ systems. A review of transplant outcomes in patients with mitochondrial disease found that, excluding one specific genetic subtype (POLG-related disease), post-transplant survival was comparable to what is seen in non-mitochondrial patients. The authors concluded that a mitochondrial diagnosis alone should not exclude someone from receiving a transplant, though POLG-related disease warrants additional caution.25Molecular Genetics and Metabolism. Solid organ transplantation in primary mitochondrial disease: Proceed with caution
Xenotransplantation and the Risk Calculus of Non-Human Donors
The frontier of transplant exclusion criteria extends beyond human donors. Xenotransplantation, using organs from genetically modified pigs, has moved from theoretical to clinical in the past few years. One of the central safety concerns is porcine endogenous retroviruses (PERVs), viral sequences embedded in the pig genome that could theoretically infect a human recipient. Strategies to manage this risk include selecting pigs that lack certain viral subtypes, using RNA-based gene silencing, and even editing the pig genome to inactivate the viruses entirely.26PubMed Central. Porcine Endogenous Retroviruses and Xenotransplantation
Regulatory bodies worldwide have developed screening standards for these animal donors. The FDA requires testing for active PERV, while the European Medicines Agency and WHO recommend comprehensive screening protocols. Donor pigs are sourced from pathogen-free herds and undergo rigorous viral testing.27PubMed. Harmonizing International Regulatory Standards for Porcine Endogenous Retrovirus (PERV) Screening in Genetically Modified Porcine Donors for First-in-Human Pancreatic Islet Xenotransplantation In a sense, xenotransplantation inverts the usual exclusion question. Rather than asking which human donors are too risky, it asks how much engineering is needed to make a non-human donor safe enough. The answer, so far, is a great deal of engineering, but the field is moving fast enough that pig-to-human transplants are no longer hypothetical.