title: Beta-trace protein-based equations for calculation of GFR in renal transplant recipients.
abstract: 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.
authors.affiliation: Department of Internal Medicine, University of Bonn, Bonn, Germany. dr.poege@nephrologie-bonn.de
authors.forename: U
authors.initials: U
authors.lastname: Pöge
authors.forename: T
authors.initials: T
authors.lastname: Gerhardt
authors.forename: B
authors.initials: B
authors.lastname: Stoffel-Wagner
authors.forename: H
authors.initials: H
authors.lastname: Palmedo
authors.forename: H-U
authors.initials: HU
authors.lastname: Klehr
authors.forename: T
authors.initials: T
authors.lastname: Sauerbruch
authors.forename: R P
authors.initials: RP
authors.lastname: Woitas
mesh_terms: D015331:Cohort Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000097:blood*; D007677:Kidney Function Tests; D016030:Kidney Transplantation; D054834:Lipocalins / Q000097:blood*; D008297:Male; D008875:Middle Aged
chemical_list: D054834:Lipocalins; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase