Deproteinization of serum: another best approach to eliminate all forms of bilirubin interference on serum creatinine by the kinetic Jaffe reaction.

The negative interference of conjugated, unconjugated, and delta bilirubin on patient serum creatinine determined by the kinetic Jaffe reaction is the unresolved problem. We compared bilirubin interference on thirty patients' serum creatinine obtained from four analyzers, with and without deprotenization before the Jaffe reaction, to the Vitros dry enzymatic method. We found significant negative interference from bilirubin on serum creatinine in all samples directly applied to four wet chemical methods, except the one incorporated with serum blank rate. The negative interferences linearly related to bilirubin concentration. However, bilirubin did not interfere on serum creatinine obtained from all wet chemical methods incorporated with deproteinization process before the reaction. We conclude that deproteinized serum before the reaction is the best approach to eliminate all forms of bilirubin interference on serum creatinine determined by the kinetic Jaffe reaction.