CAPA (2014)

Adult2014

Cystatin C-based eGFR equation for children and adults, derived from the CAPA cohorts (Caucasian, Asian, Pediatric, and Adult)

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Calculate CAPA

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

Formula

eGFR=130×SCys−1.069×age−0.117−7\text{eGFR} = 130 \times \text{SCys}^{-1.069} \times \text{age}^{-0.117} - 7

Formula constants

SymbolDescriptionValue
130Base coefficient
−1.069Cystatin C exponent
−0.117Age exponent
−7Extrarenal cystatin C clearance constant
SCysinputSerum cystatin C (standardized)mg/L
AgeinputPatient ageyears

Required inputs

Cystatin CAge

Validated age range

1 to 120 years

Limitations

  • Requires cystatin C standardized to the international calibrator
  • More expensive than creatinine-based equations
  • Derived predominantly in Caucasian and Asian cohorts — limited validation in other populations
  • Not the KDIGO-recommended adult cystatin C equation (CKD-EPI cystatin C preferred)

Clinical notes

  • Developed in 4960 individuals across the CAPA cohorts (Caucasian, Asian, Pediatric, and Adult)
  • Valid for both children and adults
  • Uses cystatin C standardized to the international ERM-DA471/IFCC calibrator
  • Single biomarker with extrarenal clearance term (−7)
  • No sex or race factor (sex effect ≈0.99 in derivation — excluded by authors)

References

  • [1]Grubb A, et al. Generation of a new cystatin C-based estimating equation for glomerular filtration rate by use of 7 assays standardized to the international calibrator. Clin Chem. 2014;60(7):974-86. doi:10.1373/clinchem.2013.220707

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