CKiD U25 Cystatin C

Pediatric2021

Age 1-25 years cystatin C-based equation

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Calculate CKiD U25 Cys-C

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=κ×1CysC\text{eGFR} = \kappa \times \frac{1}{\text{CysC}}

Formula constants

SymbolDescriptionValue
κ\kappaAge- and sex-dependent coefficient (Female)
Age 1 to <12:79.9 × 1.004^(age − 12)
Age 12 to ≤15:79.9 × 0.974^(age − 12)
Age >15 to <18:79.9 × 0.974^(age − 12)
Age 18–25:68.3
κ\kappaAge- and sex-dependent coefficient (Male)
Age 1 to <12:87.2 × 1.011^(age − 15)
Age 12 to ≤15:87.2 × 1.011^(age − 15)
Age >15 to <18:87.2 × 0.960^(age − 15)
Age 18–25:77.1
CysCinputSerum cystatin Cmg/L

Required inputs

AgeSexCystatin C

Validated age range

1 to 25 years

Limitations

  • May not be appropriate for screening asymptomatic patients
  • Significantly underestimated GFR in healthy European children/young adults
  • Higher cost than creatinine-based equations
  • Limited availability of cystatin C testing

Clinical notes

  • For individuals ages 1 to 25 with mild-to-moderate CKD
  • May not be appropriate for screening asymptomatic patients
  • Demonstrated minimal bias in pediatric and young adult CKD populations
  • No race-based modifiers required

References

  • [1]Pierce CB, Muñoz A, Ng DK, Warady BA, Furth SL, Schwartz GJ. Age- and sex-dependent clinical equations to estimate glomerular filtration rates in children and young adults with chronic kidney disease. Kidney Int. 2021;99(4):948-956. doi:10.1016/j.kint.2020.10.047

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