Estimated Glomerular Filtration Rate; Laboratory Implementation and Current Global Status.

Area of Science:

• Nephrology
• Clinical Chemistry
• Epidemiology

Background:

• The Kidney Disease Outcomes Quality Initiative (KDOQI) recommended reporting estimated glomerular filtration rate (eGFR) with creatinine in 2002 to aid early chronic kidney disease (CKD) detection.
• Initial eGFR calculations relied on the Modification of Diet in Renal Disease (MDRD) Study equation, which used non-standardized creatinine measurements.

Purpose of the Study:

• To review the evolution of eGFR reporting and equations for CKD detection.
• To highlight the transition towards standardized creatinine assays and the development of more accurate eGFR equations.

Main Methods:

• Review of historical guidelines and recommendations for eGFR reporting.
• Analysis of the development and implementation of standardized creatinine calibration.
• Examination of newer eGFR equations, including those from the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI).

Main Results:

• Standardized creatinine calibration was implemented globally by approximately 2010, leading to modified MDRD equations.
• The CKD-EPI equation (2009) demonstrated superior accuracy over the MDRD equation, particularly for eGFR values above 60 mL/min/1.73 m².
• eGFR reporting with creatinine is now nearly universal, and standardized cystatin C assays are emerging, enabling new eGFR calculation methods.

Conclusions:

• The standardization of creatinine assays and the development of advanced eGFR equations have significantly improved the ability to detect and manage CKD.
• The availability of cystatin C-based eGFR equations offers further advancements in assessing kidney function.