The National Kidney Disease Education Program group demonstrated that MDRD equation is sensitive to creatinine measurement error, particularly at higher glomerular filtration rates. Thus, MDRD-based eGFR above 60 mL/min/1.73 m² should not be reported numerically. However, little is known about the impact of analytical error on CKD-EPI-based estimates. This study aimed at assessing the impact of analytical characteristics (bias and imprecision) of 12 enzymatic and 4 compensated Jaffe previously characterized creatinine assays on MDRD and CKD-EPI eGFR. In a simulation study, the impact of analytical error was assessed on a hospital population of 24084 patients. Ability using each assay to correctly classify patients according to chronic kidney disease (CKD) stages was evaluated. For eGFR between 60 and 90 mL/min/1.73 m², both equations were sensitive to analytical error. Compensated Jaffe assays displayed high bias in this range and led to poorer sensitivity/specificity for classification according to CKD stages than enzymatic assays. As compared to MDRD equation, CKD-EPI equation decreases impact of analytical error in creatinine measurement above 90 mL/min/1.73 m². Compensated Jaffe creatinine assays lead to important errors in eGFR and should be avoided. Accurate enzymatic assays allow estimation of eGFR until 90 mL/min/1.73 m² with MDRD and 120 mL/min/1.73 m² with CKD-EPI equation.
Keywords: CKD; CKD-EPI; Chronic Kidney Disease Epidemiology Collaboration; Creatinine; Enzymatic assays; Estimated glomerular filtration rate; GFR; IDMS; Isotope Dilution Mass Spectrometry; KDIGO; Kidney Disease Improving Global Outcomes; MDRD; Modification of Diet in Renal Disease; NKDEP; National Kidney Disease Education Program; SFBC; Scr; Société Française de Biologie Clinique; TE; Total error; chronic kidney disease; eGFR; estimated glomerular filtration rate; glomerular filtration rate; serum creatinine.
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