title: Analytical and clinical validation of the new Abbot Architect 25(OH)D assay: fit for purpose?
abstract: BACKGROUND
  We provide a clinical and analytical evaluation of the reformulated version of the Abbott Architect 25-hydroxyvitamin D assay. We compared this assay with three commercial automated immunoassays and against a VDSP-traceable liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) in six different populations. We also supplemented 40 healthy volunteers with either 600,000 IU of vitamin D2 or 100,000 of vitamin D3 to evaluate the performance of the immunoassays vs. the LC-MS/MS.
  
  
  METHODS
  Precision and limit of quantification were assessed, 25(OH)D2 and C3-epimer recovery were calculated. Two hundred and forty samples obtained in healthy Caucasians and Africans, osteoporotic, hemodialyzed and intensive care patients and 3rd trimester pregnant women were analyzed by all methods. Correlation was studied using Passing-Bablok and Bland-Altman analysis. Concordance correlation coefficient (CCC) was calculated to evaluate agreement between immunoassays and LC-MS/MS. We verified if patients were homogeneously classified with the immunoassays when they took vitamin D2 or vitamin D3 after 1, 7 and 28 days.
  
  
  RESULTS
  We observed excellent analytical features and showed a very good correlation to the LC-MS/MS results in the overall population. Compared to the other immunoassays, concordance of the new Abbott assay with the LC-MS/MS was at least similar, and often better in diseased populations. Althought the cross-reactivity with 25(OH)D2 was not of 100%, there was no significant difference in the classifications of the patients, either supplemented with D2 or D3 or after 7 or 28 days.
  
  
  CONCLUSIONS
  This modified version of the Abbott Architect assay is clearly improved compared to the previous one and presents a better agreement with the LC-MS/MS.
authors: Etienne
authors: E
authors: Cavalier
authors: Pierre
authors: P
authors: Lukas
authors: Anne-Catherine
authors: AC
authors: Bekaert
authors: Agnès
authors: A
authors: Carlisi
authors: Caroline
authors: C
authors: Le Goff
authors: Pierre
authors: P
authors: Delanaye
authors: Jean-Claude
authors: JC
authors: Souberbielle
mesh_terms: D001681:Biological Assay / Q000379:methods*; D016022:Case-Control Studies; D002853:Chromatography, Liquid; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D010024:Osteoporosis / Q000097:blood*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000097:blood*; D006435:Renal Dialysis; D053719:Tandem Mass Spectrometry; D054928:Validation Studies as Topic; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D