[The effect of urinary obstruction on the results of catheterless divided 131I hippuran clearance studies (author's transl)].

During catheterless renal 131I Hippuran clearance studies, the function of each kidney can be calculated from the area integral, which is derived from the total body curve and to segments of phase II of each nephrographic curve measured for 120 seconds after the injection. For this it is assumed that the course of this phase depends entirely on the function of the renal parenchyma and is not affected by other factors such as urinary obstruction. During investigations of obstructed kidneys, considerable discrepancies were found repeatedly between clearances calculated by this method and the operative findings of a paper thin renal parenchyma of the kidney in question. In two cases it has been shown for the first time that there is an unexpected and surprising change in phase II. It follows that urinary obstruction falsifies the results of 131I Hippuran clearance tests, leading to an overestimate of the function of the obstructed kidney.