Abstract
BACKGROUND: It is not clear which serum creatinine-based glomerular filtration rate (GFR)-estimating model performs best in kidney donors. STUDY DESIGN: Study of diagnostic accuracy. SETTING & PARTICIPANTS: From a population of 3,698 kidney donors, 255 donors underwent iohexol GFR measurement (mGFR). INDEX TEST (INTERVENTION): mGFR by means of plasma disappearance of iohexol. REFERENCE TEST OR OUTCOME: GFR was estimated (eGFR) by using the Cockcroft-Gault equation (eGFR(CG)), Mayo Clinic equation (eGFR(MC)), and Modification of Diet in Renal Disease (MDRD) Study equation (eGFR(MDRD)). RESULTS: Mean mGFR was 71.8 +/- 11.8 mL/min/1.73 m(2), and 85.5% had mGFR greater than 60 mL/min/1.73 m(2). eGFR(CG) underestimated mGFR by 3.96 +/- 13.3 mL/min/1.73 m(2) and was within 30% of mGFR 89.4% of the time. eGFR(MC) overestimated mGFR by 8.44 +/- 11.9 mL/min/1.73 m(2) and was within 30% of mGFR in 83.1% of cases. eGFR(MDRD) underestimated mGFR by only 0.43 +/- 11.7 mL/min/1.73 m(2), and the proportion within 30% of mGFR was greatest in the tested model; 94.1% of the time. However, eGFR(MC) was most accurate in classifying donors according to having eGFR less than 60 mL/min/1.73 m(2). LIMITATIONS: Lack of ethnic diversity and response bias. CONCLUSIONS: The MDRD Study equation is least biased, and because it is routinely reported by most laboratories, it is the best readily available model for estimating GFR in kidney donors.