Practical Approach to Eliminate Bilirubin Interference in Icteric Samples for Creatinine Measurement

The interference of bilirubin in both kinetic alkaline picrate creatinine assays (Jaffe) and enzymatic creatinine assays has been known and described in the literature (1, 2). Bilirubin negatively interferes with the Jaffe method, leading to underestimation of creatinine concentrations. Oxidation of bilirubin to biliverdin in alkaline solutions decreases the absorbance of both the creatinine picrate complex and bilirubin at the absorbance peak of 510 nm and increases the absorbance of biliverdin at the absorbance peak of 620 nm (3). However, bilirubin interference in the Jaffe method seems rather …