title: Proficiency testing of 25-hydroxyvitamin D (25-OHD) assays.
authors.affiliation: Clinical Biochemistry, Imperial College Healthcare NHS Trust, Charing Cross Hospital, Fulham Palace Road, London W6 8RF, UK. b.carter1@which.net
authors.forename: G D
authors.initials: GD
authors.lastname: Carter
authors.forename: J L
authors.initials: JL
authors.lastname: Berry
authors.forename: E
authors.initials: E
authors.lastname: Gunter
authors.forename: G
authors.initials: G
authors.lastname: Jones
authors.forename: J C
authors.initials: JC
authors.lastname: Jones
authors.forename: H L J
authors.initials: HL
authors.lastname: Makin
authors.forename: S
authors.initials: S
authors.lastname: Sufi
authors.forename: M J
authors.initials: MJ
authors.lastname: Wheeler
mesh_terms: D001681:Biological Assay; D019963:Clinical Chemistry Tests; D019411:Clinical Laboratory Techniques / Q000592:standards; D003199:Computer Systems; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods / Q000592:standards*; D006801:Humans; D007753:Laboratories / Q000592:standards; D015203:Reproducibility of Results; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D