CKD-EPI 2021

Chronic Kidney Disease Epidemiology Collaboration

CKD-EPI creatinine equation for adults, refit without a race term

Biomarkers
Creatinine
Validated for
18+ years
Inputs
Age, Sex, Creatinine
Reports
mL/min/1.73 m²
Published
2021

The eGFR guide explains which equation the calculator suggests and indexed and absolute GFR.

Formula

eGFR=142×min⁡(Scr/κ,1)α×max⁡(Scr/κ,1)−1.200×0.9938age×sex factor\text{eGFR} = 142 \times \min(S_{cr}/\kappa, 1)^{\alpha} \times \max(S_{cr}/\kappa, 1)^{-1.200} \times 0.9938^{\text{age}} \times \text{sex factor}

As text: eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^(-1.200) × 0.9938^age × sex

Constants

SymbolMeaningValue
142Base coefficient
κ\kappaSex-dependent creatinine coefficient
Female: 0.7mg/dL
Male: 0.9mg/dL
α\alphaExponent when SCr/κ < 1
Female: −0.241
Male: −0.302
−1.200Exponent when SCr/κ ≥ 1
0.9938Age decay factor (base for age exponent)per year
Sex factorSex-dependent multiplier
Female: 1.012
Male: 1.000
ScrS_{cr}Serum creatinine (input)mg/dL
AgePatient age (input)years

How it was developed

Refitted without a race term on the CKD-EPI 2009 development data: 10 studies with 8,254 adults aged 18 or older, with GFR measured by urinary or plasma clearance of exogenous filtration markers. External validation used a new data set of 12 studies (4,050 participants).

Clinical notes

  • NKF-ASN Task Force called for its immediate use in all US laboratories
  • Listed among validated GFR estimating equations in KDIGO 2024

Limitations

  • Studied in ambulatory adults without serious coexisting conditions, not acute care
  • Few participants from racial and ethnic groups other than Black and White
  • Creatinine may mislead with extreme body habitus, sarcopenia or spinal cord injury

References

  1. Inker LA, Eneanya ND, Coresh J, et al. New creatinine- and cystatin C-based equations to estimate GFR without race. N Engl J Med. 2021;385(19):1737-1749. doi:10.1056/NEJMoa2102953
  2. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4S):S117-S314. doi:10.1016/j.kint.2023.10.018
  3. Delgado C, Baweja M, Crews DC, et al. A unifying approach for GFR estimation: recommendations of the NKF-ASN Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease. Am J Kidney Dis. 2022;79(2):268-288. doi:10.1053/j.ajkd.2021.08.003

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