Doctors consider organ donation when a patient has suffered a catastrophic injury, typically to the brain, and either has been declared brain dead or is expected to die after life-sustaining treatment is withdrawn. The process begins earlier than most people realize. Hospitals are required to notify their regional organ procurement organization (OPO) not only after a death but when death appears imminent, often while the patient is still receiving intensive care.
The First Step: Notifying the Organ Procurement Organization
Federal regulations require every hospital to have a written agreement with a designated OPO and to report all deaths and “imminent deaths.” But there is no single national standard defining which bedside signs should trigger that call. Most hospitals follow guidance from their local OPO, and those criteria vary widely. A review of 55 out of 56 U.S. OPOs found marked inconsistency: about 69% used a Glasgow Coma Scale threshold (a scoring system that rates a patient’s level of consciousness), and roughly 55% used the loss of brainstem reflexes as a trigger, but the specific cutoffs differed from one organization to the next.
This early notification is not a decision to pursue donation. It simply alerts the OPO so a coordinator can begin evaluating whether donation is medically possible while the treating team continues to focus entirely on the patient’s care.
Brain Death: The Most Common Path to Donation
The majority of deceased organ donors are patients declared brain dead. Brain death means the entire brain, including the brainstem, has permanently and irreversibly stopped functioning. It is a legal death, even though a ventilator can keep the heart beating and organs oxygenated temporarily.
To make this determination, doctors must first establish the cause of the catastrophic brain injury and rule out anything that could mimic brain death, such as severe hypothermia, drug intoxication, or metabolic imbalances. Once those factors are excluded, the clinical exam tests brainstem function at every level: checking whether the pupils respond to light, whether the eyes move when the head is turned or cold water is introduced to the ear canal, and whether there is any cough or gag reflex. The final component is an apnea test, in which the ventilator is briefly disconnected to see if the patient makes any effort to breathe on their own. If there is no respiratory drive and no brainstem reflexes, the patient meets the criteria for brain death.
How the Process Differs for Children
The core exam is largely the same regardless of age, but the timelines are longer for younger patients. For infants and children under 24 months, doctors must wait at least 48 hours after the acute brain injury before even beginning the evaluation. For patients 24 months and older, the minimum waiting period after certain types of brain injury is 24 hours. Children also require two separate apnea tests, one after each clinical examination, compared to the single test required for adults.
In infants younger than 6 months, the exam includes checking for the absence of sucking and rooting reflexes, which are unique to early development and wouldn’t be part of an adult evaluation.
Donation After Circulatory Death
Not every potential donor meets the criteria for brain death. Some patients have suffered devastating neurological injuries but still retain minimal brainstem activity. When the family and medical team decide to withdraw life-sustaining treatment because further care is futile, donation after circulatory death (DCD) becomes an option.
In this scenario, the ventilator is removed and doctors wait for the heart to stop on its own. Once it does, there must be a sustained period of no heartbeat, generally 2 to 5 minutes depending on the state and hospital protocol, before the patient is declared dead. Only then can organ recovery begin. Because organs lose viability quickly without blood flow, many transplant centers set a maximum acceptable window between the withdrawal of care and cardiac arrest. If the heart continues beating beyond that window, donation may no longer be feasible.
Why Timing Matters: Organ Viability Windows
Once organs are removed from a donor, the clock starts. Each organ tolerates time without blood flow differently, and these windows shape how urgently the transplant team needs to act.
- Heart: roughly 4 hours before outcomes decline significantly
- Lungs: generally 6 to 8 hours, though some centers accept up to 12
- Liver: ideally under 12 hours, with graft survival dropping notably beyond 16 hours
- Kidneys: the most resilient, safely preserved for 24 to 40 hours with modern preservation fluids, though outcomes are best when cold storage stays between 7 and 12 hours
These time constraints explain why OPOs begin their coordination work before the patient has died. Matching organs to recipients, arranging surgical teams, and organizing transport all need to happen quickly once donation proceeds.
What Disqualifies Someone From Donating
Doctors evaluate every potential donor individually, and far fewer conditions are automatic disqualifiers than most people assume. Age alone does not rule someone out, nor do many chronic conditions. The screening focuses primarily on two risks: transmitting an infection or transmitting cancer to the recipient.
Absolute contraindications include active metastatic cancer, acute leukemia or lymphoma in progress, multiple myeloma, and melanoma without at least five years of follow-up. On the infection side, diseases with no effective treatment (like rabies), severe systemic infections from certain intracellular pathogens, viral encephalitis of uncertain origin, and active fungal or opportunistic infections all rule out donation. Bacterial infections found in ICU patients, which are common after invasive procedures, do not automatically disqualify a donor. The goal is to identify unacceptable transmission risks, not to screen for every possible infection.
Separation Between Treatment and Donation Teams
One concern families often have is whether the possibility of organ donation could influence the care their loved one receives. Medical systems are designed to prevent this. The doctors and nurses treating a critically ill patient are separate from the transplant and organ recovery teams. In many countries this separation is written into law. In the Netherlands, for example, the physician who determines death is legally prohibited from being involved in removing or implanting any organs.
The decision to withdraw life-sustaining treatment is made based solely on the patient’s prognosis, independent of any donation consideration. Only after that decision has been made, and typically after the family has been informed that further treatment is futile, does the conversation about donation begin.
Living Donation: A Different Evaluation Entirely
Organ donation isn’t limited to patients who have died. Living donation, most commonly of a kidney, follows a completely separate pathway. Here, doctors evaluate a healthy volunteer to confirm that donating won’t put them at unacceptable risk.
The screening starts with blood and urine tests to assess kidney function and confirm compatibility with the recipient. A full physical exam and health history follow. Donors over 50 typically undergo cardiac stress testing, a chest X-ray, a colonoscopy, and a CT scan of the kidneys to map blood vessel anatomy and check for kidney stones.
A psychosocial evaluation is a required part of the process. A clinical social worker interviews the potential donor to make sure they are donating voluntarily, free from pressure, and understand both the short-term and long-term risks. The interview also assesses whether the donor has adequate support at home for recovery and screens for mental health concerns, substance use, and high-risk behaviors that could affect the recipient. If there is any history of depression, anxiety, or psychiatric treatment, a transplant psychiatrist may also be involved. Federal law prohibits receiving anything of value in exchange for a living organ donation.
The Scale of the Need
As of December 2025, more than 108,000 people were on the national transplant waiting list. The gap between available organs and people who need them is the reason hospitals are required to refer every potential donor, why OPOs coordinate so aggressively, and why the medical community continues to expand the criteria for who can be considered. Every potential donor is evaluated on their own merits, because a single donor can save or improve the lives of multiple recipients.