KEY POINTS: Living kidney donors with discordant values of measured GFR were at increased risk of developing eGFR <
45 ml/min per 1.73 m BACKGROUND: When GFR is measured (measured GFR [mGFR]) using iohexol plasma clearance, results are reported both as nonindexed (ml/min) and body surface area (BSA) indexed to 1.73 m METHODS: Between January 1, 2007, and January 1, 2023, 627 adult living kidney donors (LKD) at the University of Minnesota had predonation mGFR by iohexol plasma clearance and a minimum 6-month follow-up. LKD acceptance was based on a nonindexed mGFR ≥80 ml/min (age younger than 60 years) or ≥75 ml/min (age 60 years and older). Primary outcomes included eGFR at 1 year postdonation and sustained eGFR <
45 ml/min per 1.73 m RESULTS: Among 627 LKDs, 561 (90%) had both a nonindexed and BSA-indexed mGFR above the age-based threshold (concordant), while 66 (11%) had nonindexed measurements above and BSA indexed below (discordant). Compared with concordant LKDs, discordant LKDs were older (median: 54.1 versus 42.8 years, CONCLUSIONS: Discordant LKDs had lower eGFR measurements postdonation and experienced a higher risk of eGFR <
45 ml/min per 1.73 m