Genetic Evaluation Practices in Living Kidney Donor Candidates

Although genetic testing is increasingly used in evaluating living kidney donor (LKD) candidates and recipients, objective data on genetic testing practices are limited. This study aimed to describe current genetic testing practices in LKD evaluation using data from the international living donor genetic registry.

A research electronic data capture (REDCap) registry was developed to collect cross-sectional, deidentified information on LKD candidates and genetic test results. Participating centers registered candidates meeting at least 1 of the following criteria: (i) underwent genetic testing; (ii) family history of genetic kidney disease; and/or (iii) were evaluated to donate to a biologically related recipient with kidney disease of unknown etiology. Data were collected between June 1, 2023 and November 10, 2025.

Among 1259 LKD evaluations from 24 centers (10 US, 14 international), genetic testing was performed in 295 (23.4%). US donor candidates were younger (median 39 vs. 48 years, P < 0.001). Testing strategies differed by region as follows: international centers predominantly used recipient-first testing (92.1%), whereas US centers more often performed direct LKD testing (61.5%; P < 0.001). These differences persisted after excluding apolipoprotein L-1 (APOL1) testing, with direct LKD candidate testing remaining more common in US (34.0% vs. 7.9%; P < 0.001). Among tested LKD candidates, 20.7% (61/295) were not approved for donation, with 7.8% (23/295) attributed to genetic findings. In multivariable analysis, younger donor age was independently associated with LKD nonacceptance (adjusted odds ratio [OR]: 0.89 per-year; 95% confidence interval [CI]: 0.83-0.95; P < 0.001).

Genetic testing practices vary substantially across regions, with US centers favoring direct LKD testing and international centers using recipient-first approaches. Younger donor candidate age was independently associated with nonacceptance.