Comparison of glomerular filtration rate estimation using Jaffé and enzymatic creatinine assays in diabetic patients.

Background: Diabetic kidney disease (DKD) develops an end-stage renal failure and is a major cause of death in diabetic patients. A GFR below 60 ml/min per 1.73 m is one of the main markers of DKD. Therefore, the development of an accurate test for diagnosis and monitoring of the mentioned disease would be essential. Here, we examined the impacts of two different kits with different methods for creatinine measurement on the GFR values.

Methods: Blood samples were collected from 80 diabetic patients referring to the clinical laboratory. The levels of serum creatinine were assessed using Jaffé and enzymatic assays by kits from two different manufacturers. Then to assess the eGFR levels, the MDRD equation was used. Further descriptive parameters of both methods and correlation of methods were also calculated.

Results: Descriptive analysis of the data demonstrates a slight increase in the serum creatinine measured by Jaffé assay which leads to a substantial decrease in the levels of eGFR compared to the eGFR calculated by the enzymatic assay. Moreover, eGFR over 60  in enzymatic assay was observed in 27.5% of participants while eGFR of the same participants was below 60  when it was measured by Jaffé method. Consequently, 27.5% positive discordant cases were reported by Jaffé assay followed by misclassifying them as DKD patients compared with the enzymatic assay.

Conclusion: While using Jaffé assay, a low level of eGFR is observed which generates more misclassification into the DKD group and demands to an inclusive consideration by physicians in order to diagnose and monitor the DKD patients.