Ukrainian Journal of Laboratory Medicine · Jun 30, 2026

eGFR: ADVANTAGES AND LIMITATIONS OF CKD-EPI AND EKFC EQUATIONS

By Maksymyuk HV, Мартьянова ОИ

Background: Chronic kidney disease (CKD) remains one of the leading causes of increasing morbidity and mortality worldwide. Although creatinine is the primary biomarker used to assess kidney function, it has several important limitations. For a more accurate estimation of glomerular filtration rate (eGFR), the recommendations of KDIGO 2024 and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) should be considered. Objective: To review current approaches to kidney function assessment and evaluate the role of cystatin C, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, and the European Kidney Function Consortium (EKFC) equations in the early detection of CKD. Materials and methods: An analysis of the KDIGO 2024 clinical practice guideline, EFLM publications, and current literature on the use of creatinine, cystatin C, and the CKD-EPI and EKFC equations for estimating eGFR was performed. Results: Despite its widespread use in routine clinical practice, creatinine is an insufficiently sensitive biomarker for the early detection of impaired kidney function. Its concentration is influenced by numerous interfering substances and preanalytical factors, including muscle mass, physical activity, dietary intake, and other biological variables. Furthermore, the commonly used Jaffe method for creatinine measurement has lower analytical specificity than enzymatic assays. In contrast, cystatin C is a more stable biomarker, particularly valuable in older adults and in patients with cachexia or malnutrition. The use of combined creatinine–cystatin C equations improves the accuracy of eGFR estimation and reduces the impact of biological variability. Reliable assessment of kidney function also requires standardized laboratory methods, traceability to international reference materials, and appropriate reporting of eGFR results. As the CKD-EPI 2021 equation was primarily validated in North American populations, it does not always provide optimal accuracy in European populations and tends to systematically overestimate eGFR. This may lead to underestimation of CKD severity and inaccurate patient risk stratification. Several studies suggest that clinical laboratories should consider implementing the EKFC equation, which is better adapted to the demographic and biological characteristics of European populations. The EKFC equation enables consistent assessment of kidney function across different age groups while providing improved analytical agreement and clinical interpretation of eGFR results. Conclusions: Implementation of the KDIGO 2024 recommendations into routine laboratory practice is essential for improving the quality of CKD diagnosis and facilitating its early detection. The EKFC equation appears to be a more appropriate tool for estimating glomerular filtration rate in European populations.

doi.org/10.62151/2786-9288.4.1-2.2026.09Open accessBiomarkers