Table 3.

Performance of estimating equations compared with GFR based on inulin single-injection method in children with a solitary functioning kidney

EquationMean Bias (ml/min per 1.73 m2)a95% Limits of Agreement (ml/min per 1.73 m2)bProportion of eGFR within ±30% of GFR-Inulin (%)Proportion of eGFR within ±10% of GFR-Inulin (%)
eGFR-Schwartz0.4−35.2 to 36.19033
Ccreat−29.9−96.5 to 36.75514
eGFR-Zappitelli1−1.2−32.9 to 30.58746
eGFR-Zappitelli2−2.8−32.3 to 26.79044
eGFR-CKiD12.3−27.1 to 31.89446
eGFR-CKID2−0.9−25.1 to 23.39555
  • GFR-inulin, GFR based on inulin single-injection method; eGFR-Schwartz, estimated GFR based on serum creatinine; Ccreat, urinary creatinine clearance; eGFR-Zappitelli1, estimated GFR based on serum cystatin C; eGFR-Zappitelli2, estimated GFR based on serum cystatin C and creatinine; eGFR-CKiD [Chronic Kidney Disease in Children] 1, estimated GFR based on serum cystatin C; eGFR-CKiD2, estimated GFR based on serum cystatin C, creatinine, and BUN.

  • a Bias = GFR-inulin–estimated equation.

  • b 95% limits of agreement = mean bias ±1.96×SD.