🔍 /

CKD-EPI GFR Calculator (2021 Race-Free & Cystatin C)

The modern standard for GFR estimation. Supports 2021 Race-Free Creatinine, Cystatin C, and Combined equations.

User Rating 0.0 ★★★★★
Total Usage 0 times
Category Medicine & Tests

Patient Parameters

mg/dL
mg/L
Leave empty if unavailable
Is this tool helpful?

Your feedback helps us improve.

★ ★ ★ ★ ★

About

The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations are the current gold standard for estimating Glomerular Filtration Rate (eGFR) in adults. In 2021, the National Kidney Foundation (NKF) and the American Society of Nephrology (ASN) recommended the immediate adoption of the 2021 Race-Free Refit equation. This move eliminates race-based coefficients that previously overestimated GFR in Black patients, ensuring more equitable diagnosis and transplant eligibility.

This advanced calculator supports the 2021 Creatinine equation, the 2012 Cystatin C equation, and the Combined (Creatinine + Cystatin C) equation. The Combined equation is the most accurate estimator available without exogenous filtration markers, significantly reducing the margin of error in borderline CKD cases.

ckd-epi kidney nephrology cystatin c creatinine gfr 2021

Formulas

2021 CKD-EPI Creatinine Equation (Race-Free):

eGFR = 142 × min(Scrκ, 1)α × max(Scrκ, 1)-1.20 × 0.9938Age [× 1.012 if Female]

2012 CKD-EPI Cystatin C Equation:

eGFR = 133 × min(Scys0.8, 1)-0.499 × max(Scys0.8, 1)-1.328 × 0.996Age [× 0.932 if Female]

Reference Data

VariableCreatinine Eq (2021)Cystatin C Eq (2012)Combined Eq (2021)
Primary MarkerSerum CreatinineSerum Cystatin CBoth
Race CoefficientREMOVEDNONEREMOVED
Accuracy (P30)~87%~85%~92% (Highest)
Use CaseGeneral ScreeningMuscle Wasting, AmputeesConfirmation

Frequently Asked Questions

Cystatin C is less influenced by muscle mass than creatinine. It is superior for patients with amputation, neuromuscular disease, bodybuilders, or malnutrition where creatinine generation is abnormal.
Statistical re-evaluation showed that race is a social construct, not a biological determinant of kidney function. The 2021 refit averages the coefficients to create a single, unbiased formula applicable to all ancestries.
P30 represents the percentage of estimated GFR values that fall within 30% of the measured GFR (mGFR). The Combined equation offers the highest P30, meaning it is statistically the most reliable estimation method.