Creatinine Measurement in Urine Contaminated with Stool

To the Editor: Our study was initiated when we received 24-hour samples of urine contaminated with stool for evaluation of creatinine clearance. Contamination of urine by stool is a major problem in patients who are incontinent and in those who have vesicocolic fistulas. Although stool contains negligible amounts of creatinine, turbidity and nonspecific methodologic interference in the Jaffe reaction (for creatinine measurement) might affect urinary creatinine values. We tested this possibility by adding a standard amount of stool to specimens of urine with known creatinine concentrations. The amount of stool added (1 g per 10 ml of urine) was enough. . . No extract is available for articles shorter than 400 words.