Alternating use of 123I and 131I hippuran for routine postoperative monitoring of transplanted kidneys is impracticable.

During a 7-week period 123I hippuran was used instead of 131I hippuran for all renographies of transplanted kidneys on Wednesdays. Only in well functioning grafts with a diuresis above 2 ml/min during the examination a scintigraphic improvement of renal and upper urinary visualization was obtained. It is concluded that alternating routine use of the expensive 123I hippuran in control of renal grafts cannot be recommended.