*Purpose: Plasma Iohexol clearance based GFR measurement is considered an accurate measure of renal function. We compared performance of a novel trapezoidal AUC method of GFR measurement in living kidney donors, after a single dose non radioactive Iohexol injection, to previously described one compartment, 2 compartment based GFR measurements.

*Methods: We administered 5 cc of Iohexol(Omnipaque 300) intravenously to potential kidney donors and measured plasma concentrations (using LC-MS/MS) at 10, 20, 30, 50, 80, 120, 180, 240 minutes post administration and plotted against time. The total area under the plasma drug level-time curve from time zero to infinity was obtained by summation of each individual area between each pair of consecutive data points using the trapezoidal rule (Fig 1). GFR was calculated by dividing the dose administered by the AUC. 2-Compartment GFR was considered the gold standard of estimation.

*Results: Characteristics of donors and estimated GFRs are shown in Fig 2. Trapezoidal AUC GFR had an excellent correlation with the 2 compartment based GFR (Correlation coefficient of 0.94) (Fig 3) and with one compartment GFR (Correlation coefficient of 0.81). Trapezoidal AUC method tends to slightly underestimate GFR (compared to 2 compartment GFR). 6 value MDRD estimate of GFR was the closest to 2-compartment GFR.

*Conclusions: We describe a novel method of GFR measurement with excellent correlation to 2 compartment GFR.

« Back to 2019 American Transplant Congress