Kidney function and compensatory growth of the kidney in living kidney donors.

Pre- and postoperative kidney size and kidney function were studied in 46 living kidney donors aged 20-74 years. Kidney size was measured by planimetry and by estimation of a renal index. Kidney function was assessed by endogenous creatinine clearance and serum creatinine. Planimetry was superior to the renal index for expressing changes in renal size. Compensatory renal hypertrophy took place in donors up to the age of 74, but the greatest changes in renal size were observed in donors of under 40. Total renal function decreased postoperatively to about 77% of the initial level; this change in renal function was inversely correlated with age, but in all subjects studied the function remained within normal limits.