title: Measurement of serum total vitamin D (25-OH) using automated immunoassay in comparison [corrected] with liquid chromatography tandem-mass spectrometry.
abstract: BACKGROUND
  The associations of vitamin D deficiency with many nonskeletal diseases are still being discovered. We evaluated the use of an automated immunoassay to measure serum total vitamin D (25-OH) and assessed vitamin D status in a Korean adult population.
  
  
  METHODS
  We compared the Elecsys Vitamin D (25-OH) Total Assay (Roche Diagnostics) with liquid chromatography-tandem mass spectrometry (LC-MS/MS) using 300 serum samples. Total imprecision was calculated using three levels of quality control materials and serum samples. We also investigated the vitamin D status using data for 70,762 cases who had a routine health check-up in our hospitals.
  
  
  RESULTS
  The regression equation: Elecsys = 0.882 × LC-MS/MS + 6.814 (r = 0.926). Total imprecision was within 10% for all quality control materials and serum samples. The prevalence of vitamin D deficiency using cut-off values of <50 nmol/l (<20 ng/ml) were 70.3% in males and 86.4% in females, respectively. The prevalence of vitamin D deficiency was higher in younger subjects than in older subjects (P for linear-by-linear association was <0.001). Serum vitamin D levels were highest in September and lowest in February.
  
  
  CONCLUSIONS
  The Elecsys Vitamin D (25-OH) Total Assay was comparable to LC-MS/MS and appropriate for routine clinical use. Vitamin D deficiency is common in Korean adults.
authors.affiliation: Department of Laboratory Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sang-Yong
authors.initials: SY
authors.lastname: Shin
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Kwon
authors.forename: Junghan
authors.initials: J
authors.lastname: Song
authors.forename: Hyosoon
authors.initials: H
authors.lastname: Park
authors.forename: Hee-Yeon
authors.initials: HY
authors.lastname: Woo
mesh_terms: D000328:Adult; D000368:Aged; D001322:Autoanalysis; D002112:Calcifediol / Q000097:blood*; D002853:Chromatography, Liquid / Q000379:methods; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D056910:Republic of Korea / Q000453:epidemiology; D053719:Tandem Mass Spectrometry / Q000379:methods; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; D002112:Calcifediol
keywords: LC-MS/MS ; electrochemiluminescence; vitamin D