Approach to overcome the bilirubin interference in the estimation of serum creatinine by Jaffe’s method

Abstract

Introduction: Bilirubin has negative interference on creatinine measurement by routinely used Jaffe’s Kinetic method. Hence this study was conducted to find out a possible solution to the problem of bilirubin interference. Simple chemical method has been validated for serum creatinine estimation which is free from bilirubin interference. The performance of this method has been compared with the high performing enzymatic method. Aim: To estimate the serum creatinine in samples having high bilirubin level. Materials and Methods: 60 serum samples with bilirubin value>2 mg/dl were included in the study. Samples were divided into 3 groups each containing 20 samples, based on the bilirubin value. Each group was divided into two subgroups of 10 samples each. Initially serum creatinine was estimated by both enzymatic method and Jaffe’s kinetic method. Later serum creatinine was measured once again in all the subgroups by both methods after the preincubation of sample with NaOH for 5 min and deproteinization with Trichloroacetic acid. The statistical analysis is done by t test. Results: There was a significant increase in the creatinine obtained by Jaffe’s method after deproteinization and preincubation of the sample when compared to the creatinine obtained by Jaffe’s method before preincubation and deproteinization. The creatinine estimated after the deproteinization and preincubation by Jaffe’s method are similar to the creatinine obtained by enzymatic method before deproteinization and preincubation. Conclusion: Preincubation and deproteinization are the two simple approaches which can rectify the problem of negative interference of the bilirubin in estimating creatinine by Jaffe’s method.

Keywords

• serum creatinine
• pre incubation
• high bilirubin
• deproteinization