Table 2 Comparison of baseline serum creatinine estimated using Pottel and Schwartz equations (n = 541)

Mean (SD)- mg/dl

0.33 (0.08)

0.38 (0.08)

-0.038(0.01)^a

 < 0.001

Median (IQR)- mg/dl

0.31 (0.27–0.40)

0.36 (0.32–0.43)

-20.147^b

 < 0.001

Minimum, Max- mg/dl

0.21, 0.55

0.21, 0.56

 < 2 years (67)

 Mean (SD)- mg/dl

0.24 (0.01)

0.26 (0.02)

-0.026(0.01)^a

 < 0.001

 Median (IQR)- mg/dl

0.23 (0.23–0.25)

0.26 (0.26–0.28)

-14.574^b

 < 0.001

 Min, Max- mg/dl

0.21, 0.25

0.21, 0.29

Age 2 to 10 years (415)

 Mean (SD)- mg/dl

0.33 (0.06)

0.37 (0.05)

-0.044(0.01)^a

 < 0.001

 Median (IQR)- mg/dl

0.31 (0.28, 0.38)

0.36 (0.33, 0.42)

-12.232^b

 < 0.001

 Min, Max,—mg/dl

0.26, 0.45

0.30, 0.47

Age > 10 years (59)

 Mean (SD)- mg/dl

0.51 (0.03)

0.52 (0.02)

-0.016(0.01)^a

 < 0.001

 Median (IQR)- mg/dl

0.50 (0.47, 0.52)

0.52 (0.50, 0.54)

-6.680^b

 < 0.001

 Min, Max,—mg/dl

0.46, 0.55

0.49, 0.56

Mean bias, mg/dL, SD,

(95% CI)

-0.039, 0.013 (-0.040, to -0.038)

-

 < 0.001

Upper limit of agreement (95% CI)

-0.014 (-0.016, to -0.012

-

Lower limit of agreement (95% CI)

-0.063 (-0.065 to -062)

-

Mean percentage bias, %, SD (95% CI)

-11.97, 4.4 (-11.97 to -11.21)

 < 0.001

95% limits of agreement of percent bias, % lower limit (95% CI)

-20.34 (-21.03 to -19.74)

95% limits of agreement of percent bias, % upper limit (95% CI)

-2.80 (-3.45 to -2.15)

Percentage within ± 30% of Schwartz estimated baseline SCr, %

100.0%

Percentage within ± 10% of Schwartz estimated baseline SCr, %

32.2%