title: Editorial: The determination of circulating 25-hydroxyvitamin D: no easy task.
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Hollis
mesh_terms: D006403:Hematologic Tests / Q000592:standards; D006801:Humans; D015203:Reproducibility of Results; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D