Every lung offer runs a blood-group and a size gate.
Before quality even enters the picture, two hard biological filters shrink the donor pool for any candidate: ABO compatibility and thoracic size match. Together they explain why medically-fine lungs still go unplaced.
Source: OPTN/UNOS STAR file, Dec 2025 release · lung/heart-lung transplants with ABO match and donor+recipient height.
91% · 72%
91% of lung transplants are ABO-identical (another 9% ABO-compatible), and 72% fall within ±10 cm of donor–recipient height. Both gates must pass before an organ is even offered on quality.
01 · Blood group
Lungs are matched almost entirely ABO-identical
ABO match of completed lung transplants. Identity dominates; ABO-incompatible lung transplant is rare and protocol-driven.
ABO match (%)
Recipient blood type
O candidates are the largest group and can only receive O lungs — the classic blood-type bottleneck.
02 · Size
Lungs must fit the chest
Donor-minus-recipient height, a proxy for thoracic cavity fit. Most pairs cluster within a narrow band; large mismatches are avoided.
Donor − recipient height (% of transplants)
These filters compound: a given candidate sees only the slice of donors that are ABO-OK and size-OK. That shrinks the effective pool and is a mechanism behind "no recipient located" discards — objective quality assessment matters most within that already-narrow, matched slice.