How does organ donation actually work?
Through a tightly time-limited process that depends on how someone dies as much as on whether they consented — which is why donation is possible far less often than people assume.
The constraint people do not know about. Most deaths do not permit organ donation. Organs need oxygenated blood until retrieval, so donation generally requires death in a hospital setting, usually in intensive care — either after brain-stem death, where the person is ventilated and the heart still beating, or after circulatory death, following planned withdrawal of life-sustaining treatment. Only a small percentage of deaths meet the criteria, which is why the donor pool is far smaller than the number of registered donors suggests.
Tissue donation is different — corneas, skin, bone, heart valves and tendons can be donated after many more types of death and within a longer window.
The sequence: a potential donor is identified; a specialist nurse checks the register and discusses it with the family; medical and social history is reviewed for transmissible risk; blood typing and tissue matching are done; organs are offered through a national allocation system; retrieval and transplantation follow, with cold ischaemic time limits measured in hours — very short for a heart, longer for a kidney.
How allocation works. By clinical criteria — blood and tissue matching, medical urgency, waiting time, and expected benefit — not by wealth, status or who is known to the team.
Consent systems. Many countries have moved to opt-out — deemed consent —, where adults are presumed to agree unless they have recorded otherwise. In practice, families are still consulted everywhere, and a family's refusal is generally respected. This is why telling your family matters more than registering — a registration nobody knew about is frequently overridden by relatives who do not want to make a decision they were never told about.
Common misconceptions: age and most medical conditions do not automatically exclude you; donation does not disfigure the body or prevent an open coffin; it does not delay a funeral significantly; and the transplant team plays no part in the decision to withdraw treatment.
General information; law and systems differ by country.