Beta-Trace Protein-Based Equations for Calculation of GFR in Renal Transplant Recipients |
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Authors: | U. Pö ge ,T. Gerhardt,B. Stoffel-Wagner,H. Palmedo,H.-U. Klehr,T. Sauerbruch, R. P. Woitas |
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Affiliation: | Departments of Internal Medicine;, Clinical Biochemistry;and Nuclear Medicine, University of Bonn, Bonn, Germany |
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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 × BTP−0.5541× 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 . |
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Keywords: | Glomerular filtration rate kidney graft function renal transplant |
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