Kidney Transplant Evaluation Calculator

This calculator implements a partial version of the Kidney Donor Risk Index (KDRI), the deceased-donor kidney quality metric developed by Rao et al. (Transplantation, 2009) and used by OPTN/UNOS for US kidney allocation. The published KDRI combines TEN donor factors -- age, height, weight, ethnicity, history of hypertension, history of diabetes, cause of death, terminal creatinine, hepatitis C status, and donation-after-circulatory- death status -- into one multiplicative risk score, where a higher KDRI means a donor kidney is expected to fail sooner, on average, than a lower-KDRI kidney. This calculator uses only six of those ten factors (age, height, weight, hypertension, diabetes, and creatinine), omitting ethnicity, cause of death, hepatitis C status, and donation-after-circulatory-death status entirely. Because those omitted factors carry real, sometimes substantial weight in the published formula, the KDRI this tool produces will not match a real OPTN-issued KDRI for the same donor and should be read as an educational approximation, not a clinical or allocation-grade figure.

Donor age drives a U-shaped, not a straight-line, risk curve: from age 1 up to 18, risk actually DECREASES as donor age rises (reflecting elevated risk from very young donors' smaller nephron mass), then risk increases from 18 onward, and increases faster still past age 50 -- so the same 10-year age gap adds more risk above 50 than it does in early adulthood. Donor weight's effect on KDRI is one-sided: only being UNDER the 80 kg reference weight adds risk; any donor weight at or above 80 kg is treated identically (a real feature of the published formula, not a bug here), so raising weight above 80 kg does not further lower the calculated KDRI. The KDPI shown here is also an approximation -- the real KDPI is a percentile ranking against the actual national donor pool for a given year, recalculated annually from a published reference table, not a fixed mathematical formula, so this tool's logistic-curve estimate will not exactly match a real annual KDPI mapping. Age Match Score is a separate, simplified compatibility heuristic this tool adds on top of KDRI/KDPI; it is not part of the published Rao formula or of actual organ allocation criteria.