Creatinine Determination with Minimized Interference

Chung, Hee Jung; Chun, Sail; Min, Won Ki

Abstract

Serum creatinine has been widely used clinically as an important index for kidney function. Kinetic Jaffe assay is used for serum creatinine analysis at about 80% of clinical laboratories in Korea. There are two major interferences when creatinine level is measured by kinetic Jaffe method. One is Jaffelike chromogen, which causes positive interference, and the other is bilirubin that creates negative interference. Positive interference created by Jaffelike chromogen can be easily corrected by subtracting 0.3 mg/dL (arithmetic compensation), which is average interference by Jaffelike chromogen in normal serum, from the measured creatinine value by kinetic Jaffe method. The interference created by bilirubin can be eliminated by rate blanking which corrects the rate of change in absorbance by bilirubin from the absorbance change by Jaffe reaction. Compensated rate-blanked Jaffe kinetic assay employs above two major corrections. In clinical laboratories currently using kinetic Jaffe Method, simple application of "compensated rate-blanked Jaffe kinetic assay" can determine serum creatinine values that minimizing major interferences without change of reagent.