title: Performance evaluation of automated assays for beta-CrossLaps, N-MID-Osteocalcin and intact parathyroid hormone (BIOROSE Multicenter Study).
abstract: BACKGROUND
  Biochemical markers of bone metabolism have been mainly determined manually until now and the precision and accuracy of these methods have not always been satisfactory. This has been shown in several external quality assessment schemes (EQAS).
  
  
  OBJECTIVE
  A study named BIOROSE was undertaken to evaluate new automated assays for serum markers of bone metabolism. The main focus was to evaluate the assay performance in a multicenter setting with 20 laboratories participating in Germany. The evaluation consists of a familiarization phase to determine precision and accuracy and an EQAS to evaluate the comparability between laboratories.
  
  
  METHODS
  The parameters beta-CrossLaps (CTX), N-MID-Osteocalcin (OC) and intact parathyroid hormone (PTH) were measured with reagents including calibrators and control sera obtained from Roche Diagnostics, Mannheim, Germany, with electrochemiluminescence immunoassays (ECLIA) on the automated analyzer Elecsys 2010.
  
  
  RESULTS
  We calculated for the control samples, PCB 1-3, the mean and median values from the measured values of all participating laboratories and used these as target values. From these target values, a recovery range for the participating laboratories was calculated for beta-CrossLaps, OC and intact PTH of better than 80-126% for PCB 2 and PCB 3, and for PCB 1 (low concentration range) for beta-CrossLaps 79-129%, OC 90-120% and intact PTH 78-126%. The between-day imprecision was 2.4-7.2% for beta-CrossLaps, 1.1-5.9% for OC and 1.7-5.5% for intact PTH in the elevated range (sample PCB 2). In the EQAS, the inter-laboratory imprecision for beta-CrossLaps in the sample with a value of 0.8 ng/ml (above the upper limit of normal, which is 0.6 ng/ml) was 9.8% on day 1 and 9.7% on day 2.
  
  
  CONCLUSIONS
  The performance evaluation of automated assays for beta-CrossLaps, N-MID-Osteocalcin and intact parathyroid hormone in the BIOROSE multicenter study showed that the participating laboratories had no problems in setting up these methods and they yielded results for precision and accuracy that are superior to results achieved in external quality assessment schemes for manually performed methods. In addition, at the clinically important decision level of the upper limit of the normal range, all three tested analytes gave precise results that improved medical decisions.
authors.affiliation: Department of Endocrinology and Oncology, Limbach Laboratory, Im Breitspiel 15, 69126 Heidelberg, Germany. prof.schmidt-gayk@docnet.de
authors.forename: Heinrich
authors.initials: H
authors.lastname: Schmidt-Gayk
authors.forename: Eberhard
authors.initials: E
authors.lastname: Spanuth
authors.forename: Jochem
authors.initials: J
authors.lastname: Kötting
authors.forename: Reiner
authors.initials: R
authors.lastname: Bartl
authors.forename: Dieter
authors.initials: D
authors.lastname: Felsenberg
authors.forename: Johannes
authors.initials: J
authors.lastname: Pfeilschifter
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Raue
authors.forename: Heinz Jürgen
authors.initials: HJ
authors.lastname: Roth
mesh_terms: D001331:Automation / Q000379:methods; D015415:Biomarkers / Q000097:blood; D001842:Bone and Bones / Q000378:metabolism; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003094:Collagen / Q000097:blood*; D006801:Humans; D015675:Osteocalcin / Q000097:blood*; D010281:Parathyroid Hormone / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D010446:Peptide Fragments; C110762:glutamyl-lysyl-alanyl-histidyl-aspartyl-glycyl-glycyl-arginine; D015675:Osteocalcin; D003094:Collagen