title: Is beta-trace protein an alternative marker of glomerular filtration rate in liver transplant recipients?
abstract: BACKGROUND
  Renal insufficiency is common after liver transplantation (LT). The use of creatinine (Crea) as a marker of the glomerular filtration rate (GFR) is limited in patients after LT. Beta-trace protein (BTP), an alternative marker of GFR, is independent of muscle mass and has not been evaluated in LT recipients.
  
  
  OBJECTIVE
  To evaluate BTP as an alternative tool to monitor renal function in LT recipients.
  
  
  METHODS
  We determined the diagnostic performance of BTP in comparison to Crea and cystatin C (CysC) in 52 patients, who concomitantly underwent (99m)Tc-DTPA-clearance measurements. Furthermore, we evaluated bias, precision and accuracy of five recently developed BTP-based equations to estimate GFR.
  
  
  RESULTS
  The average measured GFR was 51 (46.1; 56.0) ml/min/1.73 m(2). Using a cut-off of 30 ml/min/1.73 m(2) the area under the curve (AUC) was nearly identical for all markers. At a decision point of 60 ml/min/1.73 m(2) BTP showed only a trend towards a higher AUC compared with Crea and CysC (0.806 vs. 0.754 and 0.760, respectively; P>0.2). In comparison to the modification of diet in renal disease-formula (MDRD) only one of five BTP-based equations displayed a significantly higher accuracy within 30% of the measured GFR (84.6 vs. 59.6%; P=0.006). None of these equations showed a significant improvement compared with MDRD with respect to bias and precision.
  
  
  CONCLUSIONS
  Beta-trace protein can be used as an alternative diagnostic tool to detect moderate or severe GFR reduction in patients after LT. Furthermore BTP-based equations are able to estimate GFR in LT recipients. However, these equations fail to perform constantly better than the MDRD formula.
authors: Department of Internal Medicine I, University of Bonn, Bonn, Germany. tm.gerhardt@web.de
authors: Thomas
authors: T
authors: Gerhardt
authors: Uwe
authors: U
authors: Pöge
authors: Birgit
authors: B
authors: Stoffel-Wagner
authors: Holger
authors: H
authors: Palmedo
authors: Tilman
authors: T
authors: Sauerbruch
authors: Rainer P
authors: RP
authors: Woitas
mesh_terms: D015415:Biomarkers / Q000097:blood; D004796:Clinical Enzyme Tests; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood; D005260:Female; D005858:Germany; D005919:Glomerular Filtration Rate; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000097:blood*; D007668:Kidney / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D054834:Lipocalins / Q000097:blood*; D016031:Liver Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D051437:Renal Insufficiency / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D012720:Severity of Illness Index; D016284:Technetium Tc 99m Pentetate; D014508:Urea / Q000097:blood
chemical_list: D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D054834:Lipocalins; D019275:Radiopharmaceuticals; D014508:Urea; D003404:Creatinine; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase; D016284:Technetium Tc 99m Pentetate