How does organ donation work?

Deceased organ donation: when a person dies in hospital — either from brain death (DBD) or after withdrawal of life-sustaining treatment (DCD) — hospital transplant coordinators assess the patient's suitability for donation, identify consent status (opt-out register, opt-in register, or family discussion), and — if consent is given — proceed to organ assessment, allocation (to matching patients on waiting lists), retrieval and transplantation. The waiting list allocation follows strict medical criteria (blood type, tissue type matching, clinical urgency, waiting time, geographic factors) — not wealth or social status. Living donation: an individual donates one kidney (or a liver segment) directly to a compatible recipient — either directed (to a known person) or non-directed (to a stranger on the waiting list).

Why is there such a shortage of organs?

The gap between demand and supply has several causes: Demand is rising: more patients with end-stage organ failure (from diabetes, hypertension, cancer, NAFLD); improved transplant survival rates mean more patients survive longer and need re-transplantation; ageing populations. Supply is limited: deceased donation requires hospital death with suitable circumstances (brain death or controlled DCD) — only a small proportion of deaths occur in suitable conditions. Low registration rates in opt-in countries. Family refusals — approximately 30-40% of otherwise suitable deceased donors are declined by families. Missed identification of potential donors.

What is the difference between opt-in and opt-out?

Opt-in (explicit consent): the default is that you are NOT a donor. You must actively register your wish to donate organs after death. If no registration and no decision made in life, families are typically asked to decide. Opt-out (presumed consent): the default is that you ARE a donor. You must actively register your wish NOT to donate. If no opt-out registration, consent is presumed. Evidence: opt-out countries consistently achieve approximately 25-30% higher deceased donation rates than opt-in countries with similar healthcare systems. The UK adopted opt-out in England, Scotland and Wales (2019-2021) — donation rates are improving.

What is xenotransplantation and is it close to becoming routine?

Xenotransplantation is transplanting organs from genetically modified pigs into humans. Pigs are the preferred source: similar organ size, well-characterised genetics, can be genetically modified extensively. The genetic modifications: knock out pig genes causing hyperacute rejection (GGTA1, B4GALNT2, CMAH); insert human complement-regulatory genes; knock out pig growth hormone receptor (prevent overgrowth). 2024 landmark: Richard Slayman received the first pig kidney in a living human recipient at Massachusetts General Hospital — he lived 47 days with the functioning xenokidney. This represents proof of concept. Challenges for routine use: long-term immune tolerance; porcine endogenous retrovirus (PERV) risk; organ size; regulatory framework. Clinical trials expected to accelerate in 2025-2028.

What happens medically to organ recipients?

Transplant recipients begin lifelong immunosuppression immediately after surgery — initially high doses, tapering to maintenance levels. First year: highest risk period for acute rejection, opportunistic infections (CMV most important; PCP; fungal infections; BK virus in kidney transplants). Long-term: excellent outcomes for most — kidney transplant 5-year graft survival approximately 75-80%; liver approximately 70-75%; heart approximately 70-75%. Long-term risks: chronic allograft dysfunction (progressive organ deterioration); immunosuppression complications (cardiovascular disease, post-transplant diabetes, malignancy — especially non-melanoma skin cancer and PTLD); medication side effects. Regular monitoring (blood tests, graft function, cancer surveillance) is required lifelong.

How does GMJ News cover organ donation?

GMJ News covers WHO transplantation data, the global organ shortage, Spain's donation model, opt-out systems, living donation, xenotransplantation 2024 breakthrough, tacrolimus immunosuppression, organ trafficking (WHO Resolution 63.22), and transplant-related malignancy risk. Organ donation is directly relevant to PHIG's hospital accreditation programme and Georgia's transplant policy development.

Home › Topics › Organ Donation and Transplantation

Organ Donation and Transplantation

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

Solid organ transplantation — offering life-saving or life-enhancing outcomes for patients with end-stage organ failure — performed approximately 89,000 transplants globally in 2022 (IRODaT), with kidneys (most common), livers, hearts, lungs and pancreata transplanted, yet faces a catastrophic global shortage: approximately 20 patients die every day in the US alone while waiting for an organ, and the gap between organ availability and need is widening in virtually every country (WHO). Spain — with the world’s highest donation rate (46 per million population) — demonstrates that system organisation (dedicated transplant coordinators, presumed consent/opt-out legislation, investment in ICU infrastructure) rather than altruism explains national differences, while the first genetically modified pig-to-human kidney transplants in living recipients (2024) represent the dawn of the xenotransplantation era.

Key messages

89K transplants/year — but demand vastly exceeds supply

89,000 solid organ transplants were performed globally in 2022 (IRODaT) — yet demand vastly exceeds supply: approximately 130,000 patients are on waiting lists globally, and approximately 20 people die every day in the US while awaiting a transplant organ (WHO).

Spain leads at 46 per million — organisation, not altruism

Spain has the world's highest deceased donation rate (46 donors per million population) — not because Spaniards are more altruistic, but because of the Sistema Nacional de Trasplantes (Transplant Coordinators embedded in every ICU) and presumed consent legislation. Organisation and infrastructure explain national differences, not culture.

Opt-out systems consistently outperform opt-in

Countries with opt-out (presumed consent) systems — Spain, France, UK (since 2020), Austria, Belgium — consistently achieve higher donation rates than opt-in (explicit consent) countries. Under opt-out, all adults are considered donors unless they have actively registered as non-donors.

Xenotransplantation — the 2024 breakthrough

In March 2024, surgeons at Massachusetts General Hospital performed the first kidney transplant from a genetically modified pig into a living human recipient. The patient survived 47 days with the functioning pig kidney before dying of unrelated causes. This marks the dawn of the xenotransplantation era after decades of preclinical research.

Living donation — expanding the pool

Living kidney donation (40,000 per year globally) and living donor liver donation (right lobe — approximately 10,000/year) significantly expand the organ pool. Kidney paired donation programmes (swapping donor-recipient pairs to create chains) enable transplantation when direct donors are incompatible.

Lifelong immunosuppression — the price of transplantation

Transplant recipients require lifelong immunosuppression — typically tacrolimus + mycophenolate ± prednisolone (triple therapy). This prevents rejection but increases susceptibility to infection and malignancy (especially skin cancer — 65-100× higher SCC risk; PTLD — post-transplant lymphoproliferative disorder).

Key statistics

89K

solid organ transplants performed globally in 2022 (IRODaT)

IRODaT/WHO

~130K

patients on global transplant waiting lists at any time

WHO/IRODaT

20/day

people die daily in US alone while waiting for an organ (HRSA)

HRSA/WHO

46/MPP

Spain: world's highest deceased donation rate (per million population)

IRODaT 2022

2024

first living human recipient of a genetically modified pig kidney (MGH/Boston)

NEJM 2024

Kidney #1

most commonly transplanted organ globally (~69,000/year)

WHO/IRODaT

Solid organ transplants by type — global 2022 (IRODaT/WHO)

Source: IRODaT 2022. Kidney transplants dominate; living donation provides approximately 40% of all kidneys.

Glossary of key terms

Opt-out (presumed consent)
WHO/IRODaTIn an opt-out organ donation system, all adults are presumed to have consented to posthumous organ donation unless they actively registered their refusal during life. Countries with opt-out: Spain (since 1979), France (2017), England (2020), Scotland (2021), Wales (2015), Austria, Belgium, many others. Consistently associated with higher donation rates. Spain's unique success also reflects investment in transplant coordination infrastructure (coordinator in every hospital ICU).

Transplant coordination — the Spanish model
ONT/WHOThe Organización Nacional de Trasplantes (ONT — Spain's national transplant organisation, founded 1989) embedded dedicated transplant coordinators in every major ICU in Spain — typically intensive care physicians trained in donation management. This identifies potential donors that would otherwise be missed, manages the family conversation professionally, and ensures seamless organ assessment and procurement. The "Spanish model" has been adopted globally as the gold standard for maximising deceased donation.

Brain death vs DCD
WHO/TransplantDonation after brain death (DBD): organs retrieved after formal brain death diagnosis (irreversible cessation of all brain function including brainstem). Donation after circulatory death (DCD): organs retrieved after cardiorespiratory arrest — either controlled (planned withdrawal of life-sustaining treatment — Maastricht category III) or uncontrolled (unexpected cardiac arrest). DCD has been expanding significantly, particularly for kidney and liver transplantation, adding substantially to the deceased donor pool.

Xenotransplantation
WHO/NEJM 2024Transplantation of organs or tissues from non-human animals into humans. The pig is the primary source — genetically modified to humanise pig organ compatibility (knocking out porcine genes that cause hyperacute rejection; inserting human complement-regulatory genes). Key milestones: 2021 (NYU): pig kidney transplanted into brain-dead human — functioned normally for 54 hours. 2024 (MGH Boston): first living human recipient of a pig kidney — patient Richard Slayman survived 47 days with the functioning xenokidney. Challenges remaining: long-term immune tolerance, porcine endogenous retroviruses (PERVs), organ size matching.

Organ trafficking (WHO Resolution 63.22)
WHOWHO Resolution 63.22 (2010) — "Human organ and tissue transplantation" — calls on member states to take measures to prevent organ trafficking and transplant tourism. The Declaration of Istanbul (2008) distinguished: legal living donation (informed consent, no payment beyond compensation for costs and lost income); illegal organ trafficking (payment for organs; coerced donation; transplant tourism). Illegal organ markets persist in some regions — primarily kidney selling — exploiting economic vulnerability. The global shortage of organs drives demand for illegal trafficking.

Tacrolimus and immunosuppression
WHO EMLStandard triple immunosuppression: tacrolimus (calcineurin inhibitor — the cornerstone; inhibits IL-2 production → T-cell proliferation suppression; narrow therapeutic index; nephrotoxic; diabetogenic) + mycophenolate mofetil (antiproliferative — inhibits de novo purine synthesis → B and T cell suppression) ± prednisolone (anti-inflammatory). Requires regular monitoring of tacrolimus blood levels. Long-term consequences: opportunistic infections, cancer (skin cancer most common), cardiovascular disease, post-transplant diabetes, nephrotoxicity.