title: First 25-hydroxyvitamin D assay for general chemistry analyzers.
abstract: 25-Hydroxyvitamin D [25(OH)D], the predominant circulating form of vitamin D, is an accurate indicator of the general vitamin D status of an individual. Because vitamin D deficiencies have been linked to several pathologies (including osteoporosis and rickets), accurate monitoring of 25(OH)D levels is becoming increasingly important in clinical settings. Current 25(OH)D assays are either chromatographic or immunoassay-based assays. These assays include HPLC, liquid chromatography-tandem mass spectrometry (LC-MS/MS), enzyme-immunosorbent, immunochemiluminescence, immunofluorescence and radioimmunoassay. All these assays use heterogeneous formats that require phase separation and special instrumentations. In this article, we present an overview of these assays and introduce the first homogeneous assay of 25(OH)D for use on general chemistry analyzers. A special emphasis is put on the unique challenges posed by the 25(OH)D analyte. These challenges include a low detection limit, the dissociation of the analyte from its serum transporter and the inactivation of various binding proteins without phase separation steps.
authors.affiliation: Diazyme Laboratories, 12889 Gregg Court, Poway, CA 92064, USA .
authors.forename: Fakhri B
authors.initials: FB
authors.lastname: Saida
authors.forename: Xiaoru
authors.initials: X
authors.lastname: Chen
authors.forename: Kiet
authors.initials: K
authors.lastname: Tran
authors.forename: Chao
authors.initials: C
authors.lastname: Dou
authors.forename: Chong
authors.initials: C
authors.lastname: Yuan
mesh_terms: D001774:Blood Chemical Analysis / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood / Q000737:chemistry / Q000378:metabolism
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-hydroxyvitamin D; CLIA; EIA; FIA; RIA; cloned enzyme-donor immunoassay; colorimetric detection; general chemistry analyzer; vitamin D binding protein