What this page shows
Every simulated patient and donor starts as one row of a synthetic file from the Edinburgh Organ Allocation Research Group. No row is a real person. The simulator holds 10,000 potential recipients and 10,000 donors, from files of 100,000 and 250,000 rows. Since 28 October 2026 the 10,000 potential recipients are drawn so that they match NHSBT’s adult elective registrations on disease mix, age and blood results. Draw a random set below and plot any two characteristics against each other, then see how the set compares with UK patients and donors.
Which characteristics come from the files, and which the model adds
Potential recipients. From the synthetic file: disease group, age, bilirubin, INR, creatinine, sodium, albumin, AFP and tumour size and number (HCC only), and the file's TBS v2 M1 value. Added by the model, exactly as the simulator does at listing: sex (by disease group), blood group (UK proportions), weight (by sex) and severe ascites (by disease group). Worked out from these: UKELD, MELD 3.0, GEMA-Na, TBS M1 and TBS with a reference donor (aged 50, DBD, intracranial haemorrhage, no diabetes). The file has no transplant centre, region, nation or blood group, and records the same sex for every row.
Donors. From the synthetic file: age and the liver centre whose area the donor hospital is in (the file covers 243 UK donor hospitals, roughly in proportion to each hospital's real donor numbers). Added by the model: DBD or DCD (48% DCD, the 2025/26 share of retrieved livers), blood group (UK proportions), sex (55% male) and weight (by sex). The donor file also holds weight and height, but the simulator does not use them.
How the potential recipients were matched to NHSBT. Each of the file’s 100,000 rows was given a weight so that, together, the rows match NHSBT’s adult elective registrations. The targets were HCC 21% and re-transplants 8%, the other disease groups in their 2025/26 shares, and age quartiles for CLD (43, 54, 61) and HCC (57, 62, 66). They also included the 2025/26 quartiles of bilirubin, creatinine, sodium, INR and albumin. The 10,000 rows were then drawn in proportion to the weights, so each row keeps its own combination of characteristics. Before matching, the file’s patients were older and sicker than UK registrations.
Super-urgent, ACLF and variant syndrome patients are made from the same recipient rows with adjusted bloods (super-urgent patients have their own), so they are not shown separately here.