Estimating Glomerular Filtration Rate (eGFR) in Clinical Practice
Primary eGFR Equations
- The National Kidney Foundation recommends using the 2021 CKD-EPI creatinine-cystatin C equation (without race) for estimating eGFR in patients with chronic kidney disease, as it provides the most accurate GFR estimates overall 1, 2
- The American College of Physicians suggests that the Cockcroft-Gault formula can be used to estimate creatinine clearance, but it may overestimate kidney function in patients with chronic kidney disease stages 3-5 3, 4
When to Use Which Equation
- The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend using serum creatinine and an eGFRcr equation for initial assessment of GFR in most patients, considering potential sources of error in creatinine-based estimates 1
- The National Institute of Diabetes and Digestive and Kidney Diseases recommends measuring cystatin C and using eGFRcr-cys when eGFRcr is thought to be inaccurate or when more accurate assessment is needed for clinical decision-making 1, 5, 6
Special Considerations
- The American Society of Nephrology recommends avoiding the use of race in eGFR calculations, as current guidelines suggest that the 2021 CKD-EPI equations have eliminated race as a variable while maintaining accuracy 1, 2, 5, 6
- The European Renal Association - European Dialysis and Transplant Association (ERA-EDTA) recommends using validated pediatric-specific equations for children and considering enzymatic creatinine assays rather than Jaffe methods in children 1, 2
Clinical Laboratory Considerations
- The College of American Pathologists recommends that laboratories implement standardized methods for creatinine and cystatin C measurement and consider offering both creatinine and cystatin C measurement capabilities 1, 2