This version was machine-translated from German and has not been medically reviewed. The authoritative version is the German version.
eGFR by CKiD U25 (creatinine + cystatin C)
Mean of the creatinine and cystatin C estimates – the most accurate variant of the CKiD U25 equations
Scientific basis
Creatinine depends on muscle mass
Serum creatinine depends on muscle mass: in malnourished children, in neuromuscular disease and in very small children, every creatinine equation overestimates GFR. Cystatin C-based equations are independent of this; in case of doubt, the guideline recommends combining both.
Calculation aid for healthcare professionals: the calculator reproduces what the sources cited assign to the inputs. Clinical assessment and every treatment decision remain with the treating physician. Inputs and results are not stored.
Frequently asked questions
eGFR by CKiD U25 (creatinine + cystatin C): What does this calculator compute?
Calculates eGFR from creatinine and cystatin C by CKiD U25 (Pierce 2021) and forms the mean of both estimates, which is more accurate and precise than either single estimate; with KDIGO category.
eGFR by CKiD U25 (creatinine + cystatin C): Which sources is this calculator based on?
Pierce CB, Muñoz A, Ng DK, Warady BA, Furth SL, Schwartz GJ: Age- and sex-dependent clinical equations to estimate glomerular filtration rates in children and young adults with chronic kidney disease (Kidney Int 99:948–956) (2021); Schwartz GJ, Muñoz A, Schneider MF et al., CKiD Study: New Equations to Estimate GFR in Children with CKD (J Am Soc Nephrol 20:629–637) – Bedside equation eGFR = 0.413 · Height / Creatinine (2009); Kidney Disease: Improving Global Outcomes (KDIGO): KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease (Kidney Int 105:S117–S314) – GFR categories G1–G5 (2024)