Usefulness of Deproteinization Using Trichloroacetic Acid for Correcting Negative Interference in Hyperbilirubinemia on Creatinine Measurement / 임상검사와정도관리

ABSTRACT

BACKGROUND: Most laboratories in Korea have been used kinetic Jaffe method for creatinine measurement. However, kinetic Jaffe method is interfered by hyperbilirubinemia, which causes creatinine decrement. In this study, we evaluated the usefulness of deproteinization by trichloroacetic acid (TCA) in eliminating negative interference of bilirubin for accurate creatinine measurement. METHODS: We evaluated the correction effect of serum creatinine levels by deproteinization using 0.55 mol/L TCA in 43 samples with various total bilirubin levels. For 26 samples of them we measured creatinine using the enzymatic method for evaluating accuracy of TCA correction. Creatinine was measured by using the Toshiba 200-FR automated analyzer and the HiSense CREA reagents. RESULTS: After TCA treatment, 22 to the total 43 samples with more than 10 mg/dL of total bilirubin, revealed statistically higher creatinine concentration (P=0.0002) and the difference of creatinine results is mean 0.53 mg/dL (0.15-1.92 mg/dL). Also, 19 of them (86.4%) revealed 20% or more difference of creatinine results before and after TCA treatment and the negative interference of bilirubin increased in proportion to the rise in total bilirubin concentration (r=0.870). There was no significant difference of creatinine results between kinetic Jaffe method with 0.55 mol/L TCA treatment and enzymatic method (P=0.216). CONCLUSIONS: TCA deproteinization is simple and very efficient method for estimating accurate creatinine level by using kinetic Jaffe method in a patient with hyperbilirubinemia.