Measurement of accidental urinary insulin loss from a dislocated intraperitoneal insulin catheter

We report the case of a type-2 diabetic woman who received continuous intraperitoneal insulin infusion and developed deterioration of metabolic control by accidental insulin loss into urine (54 U per day) as a consequence of catheter migration which probably resulted in bladder wall injury. Due to iodine allergy of this patient, an analyte addition procedure for insulin quantification in urine had to be applied to allow proof of insulin loss from the catheter tip before as well as reversal to zero insulin excretion after implantation of a new intraperitoneal port and a shorter catheter. The lost fraction of insulin accounted nearly completely for the difference between pre- and postoperatively required insulin doses (146 versus 88 U per day).