CAPA (2014)
Pediatric2014
Cystatin C-based eGFR equation derived from the CAPA cohort (Caucasian, Asian, pediatric, and adult)
Calculate CAPA
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
Formula constants
| Symbol | Description | Value |
|---|---|---|
130 | Base coefficient | |
−1.069 | Cystatin C exponent | |
−0.117 | Age exponent | |
−7 | Extrarenal cystatin C clearance constant | |
SCysinput | Serum cystatin C (standardized) | mg/L |
Ageinput | Patient age | years |
Required inputs
Cystatin CAge
Validated age range
1 to 18 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 2021 CysC preferred)
Clinical notes
- Developed in 4960 individuals across CAPA cohorts (Caucasian, Asian, pediatric, and adult)
- 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)
- Performs well across the full age range
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