Table 4.

Application of univariate cystatin C prediction equations to 1/3 validation set of 322 person-visits of the Chronic Kidney Disease in Children (CKiD) study with iGFR 44.4 ± 17.2 ml/min per 1.73m².

Equation	eGFR	Bias†	95% LOA‡	Correlation	% of eGFR within 30% of iGFR	% of eGFR within 10% of iGFR
CKiDa	44.7 ± 15.2	0.3	-17.5, 18.1	0.85	82.6%	37.6%
Zappitelli et al.b	43.5 ± 18.7	-1.0	-20.5, 18.6	0.85	77.3%	37.6%
Filler et al.c	53.5 ± 21.9	9.0	-14.0, 32.0	0.85	64.3%	21.7%
Hoek et al.d	45.0 ± 18.0	0.6	-18.4, 19.6	0.85	78.6%	37.9%

eGFR (ml/min per 1.73m²); LOA, Limits of Agreement.

^†bias = average of 322 (eGFR – iGFR) values, in ml/min per 1.73 m²

^‡95% LOA = bias ± 1.96 · standard deviation of (eGFR – iGFR)

^a70.69(cystatin C)^-0.931

^b75.94(cystatin C)^-1.170; Am J Kidney Dis. 2006; 48:221-30.

^c91.62(cystatin C)^-1.123; Pediatr Nephrol. 2003;18:981-5.

^d-4.32 + 80.35(cystatin C)^-1; Nephrol. Dial. Transplant. 2003; 18:2024-2031.