title: An evaluation of automated methods for measurement of serum 25-hydroxyvitamin D.
abstract: OBJECTIVE
  To compare two new automated assays with the well-established reference method, DiaSorin radioimmunoassay (RIA), for quantitation of serum total 25-hydroxyvitamin D [25(OH)D].
  
  
  METHODS
  25(OH)D from human sera (n=158) was measured using DiaSorin RIA and two automated platforms, DiaSorin "LIAISON 25 OH Vitamin D TOTAL", and Roche Modular "Vitamin D3 (25-OH)". Methods were compared by regression and Bland-Altman analyses.
  
  
  RESULTS
  DiaSorin LIAISON demonstrated a stronger correlation (r=0.918) and better agreement (bias=-0.88 nmol/L) with DiaSorin RIA than the Roche Modular assay (r=0.871, bias=-2.55 nmol/L). Precision ranges (CV%) for the RIA, LIAISON, and Roche Modular assays, respectively, were: within run (6.8-12.9%, 2.8-8.1%, and 1.9-5.5%), and total precision (7.4-14.5%, 7.3-17.5%, and 7.6-14.5%).
  
  
  CONCLUSIONS
  DiaSorin LIAISON displayed the best correlation and agreement with DiaSorin RIA. The DiaSorin LIAISON 25 OH Vitamin D TOTAL assay is an accurate and precise automated tool for serum total 25(OH)D determination.
authors.affiliation: Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Canada. dennis.wagner@utoronto.ca
authors.forename: Dennis
authors.initials: D
authors.lastname: Wagner
authors.forename: Heather E C
authors.initials: HE
authors.lastname: Hanwell
authors.forename: Reinhold
authors.initials: R
authors.lastname: Vieth
mesh_terms: D000328:Adult; D001667:Binding, Competitive; D006801:Humans; D008163:Luminescent Measurements / Q000295:instrumentation / Q000379:methods*; D011786:Quality Control; D011863:Radioimmunoassay / Q000295:instrumentation / Q000379:methods*; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D