CKD-EPI Cystatin C

Adult2012

eGFR calculation using cystatin C as biomarker

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Calculate CKD-EPI CysC

Enter the values required by this equation to estimate the result.

Enter all required values to see the result.

For educational and clinical reference use. Interpret results in clinical context.

Formula

eGFR=133×min⁡(SCys0.8,1)−0.499×max⁡(SCys0.8,1)−1.328×0.9962age×0.932[F]\text{eGFR} = 133 \times \min(\frac{\text{SCys}}{0.8}, 1)^{-0.499} \times \max(\frac{\text{SCys}}{0.8}, 1)^{-1.328} \times 0.9962^{\text{age}} \times 0.932^{[F]}

Formula constants

SymbolDescriptionValue
133Base coefficient
0.8Cystatin C reference valuemg/L
−0.499Exponent when SCys/0.8 < 1
−1.328Exponent when SCys/0.8 ≥ 1
0.9962Age decay factor (base for age exponent)per year
Sex factorSex-dependent multiplier
Female:0.932
Male:1.000
SCysinputSerum cystatin Cmg/L
AgeinputPatient ageyears

Required inputs

AgeSexCystatin C

Validated age range

18 to 120 years

Limitations

  • Requires standardized cystatin C assay
  • More expensive than creatinine
  • Limited availability in some settings
  • Less validation than creatinine-based equations

Clinical notes

  • Uses cystatin C as alternative biomarker
  • Less affected by muscle mass than creatinine
  • Useful for confirmatory testing
  • More expensive than creatinine-based equations
  • Recommended for specific clinical scenarios

References

  • [1]Inker LA, Schmid CH, Tighiouart H, et al. Estimating glomerular filtration rate from serum creatinine and cystatin C. N Engl J Med. 2012;367(1):20-29. doi:10.1056/NEJMoa1114248

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