Estimated or Measured GFR in Living Kidney Donors Work-up?

The value of estimated glomerular filtration rate (eGFR) in living kidney donors screening is unclear. A recently published web-based application derived from large cohorts, but not living donors, calculates the probability of a measured GFR (mGFR) lower than a determined threshold. Our objectives were to validate the clinical utility of this tool in a cohort of living donors and to test two other strategies based on chronic kidney disease epidemiology collaboration (CKD-EPI) and on MDRD-eGFR. GFR was measured using 51 Cr-ethylene-diamine tetraacetic acid urinary clearance in 311 potential living kidney donors (178 women, mean age 50 +/- 11.6 years). The web-based tool was used to predict those with mGFR < 80 mL/min/1.73 m(2). Inputs to the application were sex, age, ethnicity, and plasma creatinine. In our cohort, a web-based probability of mGFR < 90 mL/min/1.73 m(2) higher than 2% had 100% sensitivity for detection of actual mGFR <80 mL/min/1.73 m(2). The positive predictive value was 0.19. A CKD-EPI-eGFR threshold of 104 mL/min/1.73 m(2) and an MDRD-eGFR threshold of 100 mL/min/1.73 m(2) had 100% sensitivity to detect donors with actual mGFR <80 mL/min/1.73 m(2). We obtained similar results in an external cohort of 354 living donors. We confirm the usefulness of the web-based application to identify potential donors who should benefit from GFR measurement.