Beta-trace protein-based equations for calculation of GFR in renal transplant recipients

Am J Transplant. 2008 Mar;8(3):608-15. doi: 10.1111/j.1600-6143.2007.02117.x.


Recently, we showed that serum beta-trace protein (BTP) is an alternative marker of glomerular filtration rate (GFR) in renal transplant recipients (RTR). We have now developed three BTP-based GFR formulae derived by multiple regression analyses from the patients who had participated in that study. Currently, we validated the diagnostic performance of these BTP-formulae in 102 consecutive RTR who underwent a technetium diethylenetriamine pentaacetic acid (DTPA) clearance for GFR measurement in comparison to the re-expressed Modification of Diet in Renal Disease (MDRD) equation and a recently proposed BTP-based equation (referred to as 'White equation'). The best-performing BTP formula was found to be: GFR = 89.85 x BTP(-0.5541)x urea(-0.3018). This equation estimated true GFR virtually without bias (+0.43 mL/min/1.73 m(2), not significant [NS]), while a small, but significant, overestimation was seen for the MDRD formula (+3.43 mL/min/1.73 m(2), p = 0.003). Precision and accuracies within 50% of true GFR (93.1% and 88.2%, respectively) tended to be higher for the BTP formula, but the differences did not reach significance. The White equation overestimated the true GFR by 9.43 mL/min/1.73 m(2)(p = 0.001), and was inferior with respect to precision and 50% accuracy (79.4%). BTP-based GFR calculations are reliable, and may serve as an alternative to the re-expressed MDRD equation.

Publication types

  • Validation Study

MeSH terms

  • Cohort Studies
  • Female
  • Glomerular Filtration Rate*
  • Humans
  • Intramolecular Oxidoreductases / blood*
  • Kidney Function Tests*
  • Kidney Transplantation*
  • Lipocalins / blood*
  • Male
  • Middle Aged


  • Lipocalins
  • Intramolecular Oxidoreductases
  • prostaglandin R2 D-isomerase