Intraindividual variability of the modified Schwartz and novel CKiD GFR equations in pediatric renal transplant patients

Pediatr Transplant. 2011 Nov;15(7):760-5. doi: 10.1111/j.1399-3046.2011.01568.x. Epub 2011 Aug 23.


GFR in children can be obtained from a formula using SCr and height or various formulas including serum CysC. Recently, two new GFR formulas have been developed: (i) height and SCr-mSchwartz GFR and (ii) height, SCr, CysC, and serum urea (CKiD GFR). While these formulas proved to be accurate when compared to the gold standard, their use in children post-kidney Tx is yet to be assessed. A total of 1174 blood samples (urea, SCr and CysC) were analyzed from the post-Tx period in 24 Tx children (12 boys, median age = 8.6 yr) currently followed at our institution. CKiD GFR and mSchwartz GFR were compared using Bland-Altman analysis and the CV. The mSchwartz GFR overestimated the CKiD GFR (mean bias = 1.09 ± 0.14; 95% limits of agreements from 0.82 to 1.36). Median CV of CKiD GFR (10.3%) was significantly lower than that of mSchwartz GFR (15.0%), p = 0.04, and negatively correlated with the slope of GFR (r(2) = 0.34, p = 0.0026). In conclusion, CKiD GFR has a significantly lower intraindividual variation than mSchwartz GFR and may be better suited for longitudinal follow-up of patients post-Tx.

MeSH terms

  • Adolescent
  • Child
  • Child, Preschool
  • Cystatin C / blood
  • Female
  • Glomerular Filtration Rate
  • Humans
  • Immunosuppressive Agents / therapeutic use
  • Infant
  • Kidney Function Tests
  • Kidney Transplantation / methods*
  • Longitudinal Studies
  • Male
  • Nephrology / methods
  • Reproducibility of Results
  • Retrospective Studies


  • Cystatin C
  • Immunosuppressive Agents