title: 25-OH-vitamin D assay variation and subject management in clinical practice.
abstract: OBJECTIVE
  To compare two methods for assessing vitamin D status in clinical settings.
  
  
  METHODS
  25-OH-vitamin D status was measured in 120 patients by HPLC and a commercial immunoassay.
  
  
  RESULTS
  Only 53% of the subjects considered as vitamin D sufficient by immunoassay fell within this category according to HPLC although subjects with concentrations above 75 nmol/L, regardless of the method used, presented normal PTH concentrations.
  
  
  CONCLUSIONS
  Both methods are not exchangeable to classify subjects based on unique cut-offs but they are comparable when interpreted in relation with PTH concentrations.
authors.affiliation: Unidad de Vitaminas, Servicio de Bioquímica Clínica, Hospital Universitario Puerta de Hierro-Majadahonda, 28222, Madrid, Spain. fgranado.hpth@salud.madrid.org
authors.forename: F
authors.initials: F
authors.lastname: Granado-Lorencio
authors.forename: J Salazar
authors.initials: JS
authors.lastname: Mosteiro
authors.forename: C
authors.initials: C
authors.lastname: Herrero-Barbudo
authors.forename: E Donoso
authors.initials: ED
authors.lastname: Navarro
authors.forename: I
authors.initials: I
authors.lastname: Blanco-Navarro
authors.forename: B
authors.initials: B
authors.lastname: Pérez-Sacristán
mesh_terms: D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D012372:ROC Curve; D014807:Vitamin D / Q000097:blood*
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D