Pediatric Nephrology

, Volume 18, Issue 10, pp 981–985 | Cite as

Should the Schwartz formula for estimation of GFR be replaced by cystatin C formula?

  • Guido FillerEmail author
  • Nathalie Lepage
Rapid Communication


It is common practice to estimate glomerular filtration rate (GFR) from the Schwartz formula (a height creatinine/ratio), although it has its limitations. Cystatin C was found to be a superior marker of GFR. No formula has been validated to estimate GFR from cystatin C in children. Children (aged 1.0–18 years, n=536) with various renal pathologies undergoing nuclear medicine GFR clearance studies (99mTc-DTPA single-injection technique) were tested. Cystatin C was measured with a nephelometric assay. The Schwartz GFR was calculated using enzymatically determined serum creatinine in micromoles per liter using the constant 48 for adolescent males and 38 otherwise. Using multiple stepwise regression analysis on log/log-transformed data, we derived the following relationship between the cystatin C concentration and GFR: log(GFR)=1.962+[1.123*log(1/Cystatin C)]. Using the Bland and Altman analysis to test agreement between the Schwartz formula and gold standard GFR showed considerable bias, with a mean difference of +10.8% and a trend towards overestimation of the GFR by the Schwartz formula with lower GFRs. In contrast, the Bland and Altman analysis applied on the GFR estimate derived from cystatin C showed the mean difference to be negligible at +0.3% and no trend towards overestimation of the GFR with lower GFRs. In the regression analysis of the estimate and the GFR, the Schwartz estimate showed significant deviation from linearity, whereas the cystatin C estimate did not. In conclusion, the data suggest that this novel cystatin C-based GFR estimate shows significantly less bias and serves as a better estimate for GFR in children.


Cystatin C Schwartz formula 



The study was funded by a limited educational grant from Dade Behring GmbH, Marburg, Germany.


  1. 1.
    Schwartz GJ, Haycock GB, Edelmann CM Jr, Spitzer A (1976) A simple estimate of glomerular filtration rate in children derived from body length and plasma creatinine. Pediatrics 58:259–263PubMedGoogle Scholar
  2. 2.
    Schwartz GJ, Brion LP, Spitzer A (1987) The use of plasma creatinine concentration for estimating glomerular filtration rate in infants, children and adolescents. Pediatr Clin North Am 34:571–590PubMedGoogle Scholar
  3. 3.
    Seikaly MG, Browne R, Bajaj G, Arant BS Jr (1996) Limitations to body length/serum creatinine ratio as an estimate of glomerular filtration in children. Pediatr Nephrol 10:709–711PubMedGoogle Scholar
  4. 4.
    Nolte S, Mueller B, Pringsheim W (1991) Serum alpha 1-microglobulin and beta 2-microglobulin for the estimation of fetal glomerular renal function. Pediatr Nephrol 5:573–577PubMedGoogle Scholar
  5. 5.
    Filler G, Witt I, Priem F, Ehrich JHH, Jung K (1997) Are cystatin C and beta-2-microglobulin better markers than serum creatinine for prediction of a normal glomerular filtration rate in pediatric subjects? Clin Chem 43:1077–1078PubMedGoogle Scholar
  6. 6.
    Dharnidharka VR, Kwon C, Stevens G (2002) Serum cystatin C is superior to serum creatinine as a marker of kidney function: a meta-analysis. Am J Kidney Dis 40:221–226CrossRefPubMedGoogle Scholar
  7. 7.
    Bokenkamp A, Domanetzki M, Zinck R, Schumann G, Byrd D, Brodehl J (1998) Cystatin C—a new marker of glomerular filtration rate in children independent of age and height. Pediatrics 101:875–881PubMedGoogle Scholar
  8. 8.
    Filler G, Priem F, Lepage N, Sinha P, Vollmer I, Clark H, Keely E, Matzinger M, Akbari A, Althaus H, Jung K (2002) Beta-trace protein, cystatin C, beta(2)-microglobulin, and creatinine compared for detecting impaired glomerular filtration rates in children. Clin Chem 48:729–736PubMedGoogle Scholar
  9. 9.
    Russell CD (1993) Optimum sample times for single-injection, multisample renal clearance methods. J Nucl Med 34:1761–1765Google Scholar
  10. 10.
    Bland JM, Altman DG (1986) Statistical methods for assessing agreement between two methods of clinical measurement. Lancet I:307–310Google Scholar
  11. 11.
    Krouwer, JS, Monti KL (1995) A simple, graphical method to evaluate laboratory assays. Eur J Clin Chem Clin Biochem 33:525–527PubMedGoogle Scholar
  12. 12.
    Dalton RN, Haycock GB (1999). Laboratory investigation. In: Barratt TM, Avner ED, Harmon W (eds) Pediatric nephrology, 4th edn. p 355Google Scholar
  13. 13.
    Filler G, Priem F, Vollmer I, Gellermann J, Jung K (1999) Diagnostic sensitivity of serum cystatin for impaired glomerular filtration rate. Pediatr Nephrol 13:501–505CrossRefPubMedGoogle Scholar
  14. 14.
    Finney H, Newman DJ, Gruber W, Merle P, Price CP (1997) Initial evaluation of cystatin C measurement by particle-enhanced immunonephelometry on the Behring nephelometer systems (BNA, BN II). Clin Chem 43:1016–1022PubMedGoogle Scholar
  15. 15.
    Erlandsen EJ, Randers E, Kristensen JH (1999) Evaluation of the Dade Behring N Latex cystatin C assay on the Dade Behring Nephelometer II system. Scand J Clin Lab Invest 59:1–8CrossRefPubMedGoogle Scholar
  16. 16.
    Randers E, Erlandsen EJ (1999) Serum cystatin C as an endogenous marker of the renal function—a review. Clin Chem Lab Med 37:389–395PubMedGoogle Scholar

Copyright information

© IPNA 2003

Authors and Affiliations

  1. 1.Department of Pediatrics, Division of Nephrology, Children's Hospital of Eastern OntarioUniversity of OttawaOttawaCanada
  2. 2.Department of Laboratory Medicine, Children's Hospital of Eastern OntarioUniversity of OttawaOttawaCanada

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