Isotope Differential Renal Function Versus Ultrasound Measured Kidney Size in Assessing Potential Living Donors

OBJECTIVE This study evaluated a possible correlation between Mercapto Acetyl Tri Glycine (MAG3) differential renal function and kidney size measured by ultrasonography (US) and whether US alone is sufficient in deciding which kidney to donate. METHODS Between March 2003 and November 2008, 81 potential kidney donors underwent full assessment including 51‐chromium ethylenediamine tetraacetic acid (51‐Cr EDTA), glomerular filtration rate (GFR), 99mTc MAG3 renograms for differential renal function, and US to determine kidney size. Transplant outcome (estimated GFR and creatinine at 1, 3, and 6 months) was analyzed according to category of differential function (0%; 1%–10%; 11%–20%), donor sex, and donated GFR. RESULTS The mean donated GFR correlated significantly with categories of differential function (F5 4.998, p = .01). US kidney length correlated significantly with total donor GFR (right: r = 0.286, p = .016; left: r = 0.351, p = .003, respectively). Also, differential function correlated significantly with the difference in length between right and left kidneys (r = 0.333; p = .005). However, in 10 donors kidney length was inversely related to the divided renal function. DISCUSSION Donors could have their better kidneys removed if US alone is used. Differential renal function has advantages over US alone and should be used to assess all potential donors prior to kidney donation.