Table 1.

Published cystatin C–based estimated GFR equations

Equation NameEquation
Equations with serum cystatin C
    Bökenkamp et al. (2)GFR (ml/min per 1.73 m2) = 137/serum cystatin C − 20.4
    Filler and Lepage (6)GFR (ml/min per 1.73 m2) = 10^(1.962 + (1.123 × LOG(1/Cys C))
    Grubb et al. (4)GFR (ml/min per 1.73 m2) = 84.69 × serum cystatin C−1.68 × 1.384 for age <14 years
    Zappitelli et al. (CysEq) (3)GFR (ml/min per 1.73 m2) = 75.94/[serum cystatin C1.17] if renal transplant, ×1.2
Equations with serum cystatin C and serum creatinine
    Bouvet et al. (8)[(SCr (μM)/96)(−0.35 (±0.20))] · [(serum cystatin C (mg/L)/1.2)(−0.56(±0.19))] · [(body weight (kg)/45)(0.30(±0.17))] · [age (years)/14)(0.40 (±0.16))].
    CKiDa (11)eGFR= a[height (m)/Scr (mg/dl]b[1.8/cystatin C (mg/L)]c[30/BUN (mg/dl)]d[emale][height/1.4]f
    Zappitelli et al. (CysCrEq) (3)GFR (ml/min per 1.73 m2) = (507.76e0.003×height)/(CysC0.635 × SCr0.547 [μmol/L])
If renal transplant, ×1.165
If spina bifida, ×(SCr0.925 [μmol/L])/40.45
  • a We analyzed the CKiD equation with the model that did not include urea. In the original study, the inclusion of urea level in the equation improved the performance of CKiD equation to some extent as the model without urea had R2 of 69.4% and percentage of estimated GFR within 30% of measured GFR of 84% which was slightly lower than the respective values of 75% and 87.7% with the equation with urea (11). BUN, blood urea nitrogen.