title: Comparison of two 25-hydroxyvitamin D immunoassays to liquid chromatography-tandem mass spectrometry in assessing samples from the Chinese population.
abstract: BACKGROUND
  We compared the utility of two 25-OH-D immunoassays to a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for assessing human serum samples from the Chinese population.
  
  
  METHODS
  In total, 451 Chinese serum samples were tested using the IDS 25-Hydroxy Vitamin D EIA kits and the LC-MS/MS 25-OH-D method. Of these, 239 samples were also analysed using DiaSorin 25-Hydroxyvitamin D RIA kits.
  
  
  RESULTS
  The regression coefficients (r) between LC-MS/MS and immunoassays were 0.8430 (95% CI: 0.8140-0.8678) for IDS-EIA and 0.8187 (95% CI: 0.7720-0.8566) for DiaSorin-RIA. Using the Passing-Bablok analysis, IDS-EIA and DiaSorin-RIA yielded results equivalent to those from LC-MS/MS. However, IDS-EIA showed negative bias and DiaSorin-RIA showed positive bias when compared to LC-MS/MS, as indicated by the Bland-Altman plots. By the kappa test, both IDS-EIA and DiaSorin-RIA were in acceptable agreement with LC-MS/MS in the assessment of vitamin D deficiency and insufficiency.
  
  
  CONCLUSIONS
  Although some systematic bias was found, the DiaSorin-RIA and IDS-EIA kits met the minimum performance goal for 25-OH-D measurement and can be recommended for routine use in the Chinese population. However, further studies are needed to assess 25-OH-D measurement immunoassays with lower bias and that are more suitable for the Chinese population.
authors.affiliation: National Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention, Nanwei Road No. 29, Xicheng District, Beijing postcode 100050, China.
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Yun
authors.affiliation: National Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention, Nanwei Road No. 29, Xicheng District, Beijing postcode 100050, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: National Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention, Nanwei Road No. 29, Xicheng District, Beijing postcode 100050, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Yang
authors.affiliation: National Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention, Nanwei Road No. 29, Xicheng District, Beijing postcode 100050, China.
authors.forename: Yajie
authors.initials: Y
authors.lastname: Li
authors.affiliation: National Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention, Nanwei Road No. 29, Xicheng District, Beijing postcode 100050, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Piao
authors.affiliation: National Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention, Nanwei Road No. 29, Xicheng District, Beijing postcode 100050, China. Electronic address: xgyangcdc@vip.sina.com.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Yang
mesh_terms: D044466:Asian People; D002681:China; D002853:Chromatography, Liquid; D006801:Humans; D007118:Immunoassay; D012044:Regression Analysis; D053719:Tandem Mass Spectrometry; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood / Q000276:immunology
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-Hydroxyvitamin D; Agreement; Assay; Correlation; Vitamin D