Green urine in a critically ill patient.

The development of discolored urine in the critically ill patient, although uncommon, may have many possible causes, with the most likely source related to medication administration. Studies were undertaken in a 39-year-old man who developed dark green urine while in the intensive care unit for neutropenic sepsis. Although the patient had developed prior nonoliguric renal failure stemming from his sepsis, his renal function at the time of presentation of urine discoloration was considered normal. Review of his medications and intravenous infusions suggested the most likely cause was the food dye placed in his enteral tube feedings. Spectrophotometric evaluation of the urine confirmed the presence of Food Dye and Color Blue Number 1 (FD&C Blue No. 1). This case shows that significant gastrointestinal absorption of FD&C Blue No. 1 can occur. FD&C Blue No. 1 should be considered in the differential diagnosis of dark green discolored urine. Copyright 2002 by the National Kidney Foundation, Inc.