Glomerular Filtration Rate Estimation (eGFR) by CKD-EPI Equation with Creatinine and Cystatin C, without Race (2021)

 

Input
 

Sex	Female
	Male
Age		mo yr
Serum Creatinine		mcmol/L mg/dL mmol/L
Cystatin C		mcg/mL mg/L
Optional parameters to calculate patient-specific eGFR based on patient's Body Surface Area (BSA)
Height		cm inch(es) inch in mm m
Weight		gm kg lb

 

Results
 
Important: Inputs must be complete to perform calculation.

 

eGFR normalized to a BSA of 1.73 m2
eGFR		mL/min/1.73 m(2) mL/min/1.73 m2 mL/min/1.73 m^2 mL/min/1.73m2 mL/sec/1.73 m^2
eGFR without normalization to BSA
BSA		cm^2 m(2) m^2 sqcm sqm sqrcm sqrm
eGFR for this BSA		L/hr L/min L/sec mL/hr mL/min mL/sec
Decimal Precision   0 1 2 3

 

 

Notes

• In this calculator, mcg is the abbreviation for micrograms.
• The default units of measure for weight and height are kilograms and centimeters. Please verify that the correct unit of measure has been selected.
• eGFR is calculated by equations developed by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI).
• Calculated eGFR results are rounded to the nearest integer. There may be significant differences at between estimated and measured GFR on an individual patient-level.^[4]
• eGFR without normalization to BSA may be used for purposes of adjustments in medication dosing. Note that using non-normalized eGFR in obese patients can result in overestimation of GFR and potential overdosing.

 
Equations used
 

eGFR = 135 * min(Serum Creatinine/kappa, 1)alpha * max(Serum Creatinine/kappa, 1)-0.544 * min(CystatinC/0.8, 1)-0.323 * max(CystatinC/0.8, 1)-0.778 * 0.9961Age * SexFactor

BSA = 0.007184 * Height0.725 * Weight0.425

eGFR for this BSA = eGFR * BSA / 1.73

 

 

Calculation Details and Variables

• For females, the following values are used: SexFactor = 0.963; alpha = -0.219; kappa = 0.7
• For males, the following values are used: SexFactor = 1; alpha = -0.144; kappa = 0.9
• The min function returns the minimum of the 2 arguments within the parentheses. The max function returns the maximum of the 2 arguments within the parentheses.

 

References

1. Inker LA, Eneanya ND, Coresh J, et al. Chronic Kidney Disease Epidemiology Collaboration. New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race. N Engl J Med. 2021 Sep 23. PubMed ID: 34554658
2. Levey AS, Titan SM, Powe NR, et al. Kidney Disease, Race, and GFR Estimation. Clin J Am Soc Nephrol. 2020 Aug 7;15(8):1203-1212. PubMed ID: 32393465
3. Du Bois D, Du Bois EF. A formula to estimate the approximate surface area if height and weight be known. Arch Intern Med. 1916; 17:863-871.
4. Shafi T, Zhu X, Lirette ST, et al. Quantifying Individual-Level Inaccuracy in Glomerular Filtration Rate Estimation : A Cross-Sectional Study. Ann Intern Med. 2022 Aug;175(8):1073-1082. PubMed ID: 35785532