title: A Rapid and Simple Liquid-Chromatography-Tandem Mass Spectrometry Method for Measuring 25-Hydroxyvitamin D2 and 25-Hydroxyvitamin D3 in Human Serum: Comparison with Two Automated Immunoassays.
abstract: BACKGROUND
  Total 25-hydroxyvitamin D (25(OH)D) is well-known to be a reliable biomarker of human vitamin D status, with the recognition of widespread vitamin D insufficiency in general populations. The aims of this study are to validate a fast and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying 25(OH)D2and 25(OH)D3in serum and to compare two automated immunoassays with the LC-MS/MS method.
  
  
  METHODS
  Samples were prepared by protein precipitation with ethanol including 25(OH)D3-d6, followed by a liquid-liquid extraction with hexane. The analytes were separated within a total run time of 3 min. Accuracy was evaluated with standard reference materials (SRM) 972a. Using 150 samples, the LC-MS/MS method was compared with the LIAISON®assay and ADVIA Centaur®assay.
  
  
  RESULTS
  The LC-MS/MS method had a limit of quantitation of 1 ng/mL for the 25(OH)D2and 25(OH)D3with linear responses between 1 and 100 ng/mL. Intra- and inter-assay precision were <8.8% and <13.2%, respectively. It also showed a smallest mean difference (+0.9%) for the SRM level 1 to 3, compared to the two immunoassays. Compared to the LC-MS/MS, the mean biases of the RIAISON and ADVIA were +2.4 and +7.9 ng/mL, respectively. Also, the agreement of the LC-MS/MS with the RIAISON was better than that with the ADVIA.
  
  
  CONCLUSIONS
  This study suggests that the LC-MS/MS method traceable to the SRM can be reliably applied in routine quantification of 25(OH)D2and 25(OH)D3.
authors.affiliation: Department of Bioanalysis, Seoul Medical Science Institute & Seoul Clinical Laboratories, Yongin, Korea.|Companion Biomarker Center, SCL Healthcare Inc., Yongin, Korea.
authors.forename: Sanghoo
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Bioanalysis, Seoul Medical Science Institute & Seoul Clinical Laboratories, Yongin, Korea.
authors.forename: Joo-Hoon
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Bioanalysis, Seoul Medical Science Institute & Seoul Clinical Laboratories, Yongin, Korea.
authors.forename: Seol-A
authors.initials: SA
authors.lastname: Kim
authors.affiliation: Department of Diagnostic Immunology, Seoul Medical Science Institute & Seoul Clinical Laboratories, Yongin, Korea.
authors.forename: Yeoun-Soo
authors.initials: YS
authors.lastname: Sun
authors.affiliation: Department of Diagnostic Immunology, Seoul Medical Science Institute & Seoul Clinical Laboratories, Yongin, Korea.
authors.forename: Anna
authors.initials: A
authors.lastname: Lee
authors.affiliation: Department of Diagnostic Immunology, Seoul Medical Science Institute & Seoul Clinical Laboratories, Yongin, Korea.
authors.forename: Seo-Jin
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Department of Bioanalysis, Seoul Medical Science Institute & Seoul Clinical Laboratories, Yongin, Korea.
authors.forename: Yun-Tae
authors.initials: YT
authors.lastname: Kim
authors.affiliation: Department of Bioanalysis, Seoul Medical Science Institute & Seoul Clinical Laboratories, Yongin, Korea.|Companion Biomarker Center, SCL Healthcare Inc., Yongin, Korea.
authors.forename: Kyoung-Ryul
authors.initials: KR
authors.lastname: Lee
authors.affiliation: Department of Bioanalysis, Seoul Medical Science Institute & Seoul Clinical Laboratories, Yongin, Korea yjkim@scllab.co.kr.
authors.forename: Young-Jin
authors.initials: YJ
authors.lastname: Kim
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood*; D001331:Automation; D002112:Calcifediol / Q000097:blood*; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D012044:Regression Analysis; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol
keywords: 25-Hydroxyvitamin D2; 25-Hydroxyvitamin D3; Automated immunoassays; Liquid chromatography-tandem mass spectrometry