Marked variation in creatinine clearance estimation in patients receiving parenteral nutrition

We report on the marked variability of creatinine clearance in patients receiving total parenteral nutrition (TPN). 18 of 93 patients receiving TPN had serial estimations of creatinine clearance. Almost all patients had marked variation in creatinine clearance values; in some cases this exceeded 200%. In 11 of the 18 patients, the total urine output was not constant and incomplete urine collections may have accounted for the variation. However, in the remaining 7 patients, the daily urine output was fairly constant and the difference between the highest and lowest urine output during the course of TPN did not exceed 300 ml.