Urinary creatinine excretion in the ICU: low excretion does not mean inadequate collection.

Background: It has been assumed that a urinary creatinine excretion rate of less than 10 mg/kg per day means an inadequately collected urine sample.

Objective: To determine the frequency of a urinary creatinine excretion rate of less than 10 mg/kg per day in intensive care unit patients with an adequately collected urine sample.

Method: In a prospective study of creatinine excretion rates, 24-hour urine samples were evaluated for urinary creatinine in 209 critically ill patients with indwelling Foley catheters.

Prediction equation estimates of creatinine clearance in the intensive care unit.

Objective: To assess the accuracy of 4 mathematical equations used to estimate creatinine clearance versus the 24-h creatinine clearance in ICU patients.

Design: Prospective study of renal function prediction.

Setting: The general adult ICUs of 3 metropolitan hospitals.