title: Four automated 25-OH total vitamin D immunoassays and commercial liquid chromatography tandem-mass spectrometry in Finnish population.
abstract: BACKGROUND
  Comparing four fully automated 25-OH-D immunoassays to a commercially available liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with human serum samples from Finnish population.
  
  
  METHODS
  400 samples were analyzed with the Liaison Total Vitamin D, the IDS-iSYS 25-Hydroxy Vitamin D, the ARCHITECT 25-OH Vitamin D, the ADVIA Centaur Vitamin D Total, and a commercially available LC-MS/MS 25-OH D (PerkinElmer) method.
  
  
  RESULTS
  The Liaison method mean value (95% confidence intervals) was 65.6 nmol/L (62.6 - 68.6); the IDS-iSYS mean was 70.3 nmol/L (67.4 - 73.1); the ARCHITECT mean was 69.0 nmol/L (65.5 - 72.5); ADVIA Centaur mean was 71.6 nmol/L (68.9 - 74.3), and the LC-MS/MS mean was 82.8 nmol/L (79.4 - 86.2). The regression coefficients (r) between the LC-MS/MS and immunoassays were 0.650 for Liaison, 0.757 for IDS-iSYS, 0.721 for ARCHITECT and 0.684 for ADVIA Centaur. With the Passing-Bablok analysis, none of the immunoassays gave results equivalent to LC-MS/MS. Two of the four automated 25-OH-vitamin D assays (IDS-iSYS, ADVIA Centaur) were overall in good clinical agreement with LC-MS/MS, even though the results obtained with all compared methods were not equivalent.
  
  
  CONCLUSIONS
  In conclusion, in routine clinical laboratory both immunoassays and LC-MS/MS are useful for measuring 25-OH-vitamin D provided that these methods are correctly standardized and especially sample pretreatment is carefully performed.
authors.affiliation: Institute of Diagnostics, Department of Clinical Chemistry University of Oulu and Laboratory, Oulu University Hospital, Oulu, Finland.
authors.forename: Marja-Kaisa
authors.initials: MK
authors.lastname: Koivula
authors.forename: Nina
authors.initials: N
authors.lastname: Matinlassi
authors.forename: Päivi
authors.initials: P
authors.lastname: Laitinen
authors.forename: Juha
authors.initials: J
authors.lastname: Risteli
mesh_terms: D001331:Automation; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005260:Female; D005387:Finland; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008297:Male; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D