25-hydroxyvitamin D measurement, 2009: a review for clinicians.
As clinicians are more widely appreciating the endemic nature of low vitamin D status, measurement of serum 25-hydroxyvitamin D (25(OH)D), the accepted measure of vitamin D status, has increased. Challenges to 25(OH)D measurement include the presence of 2 forms of vitamin D-ergocalciferol and cholecalciferol (vitamin D(2) and vitamin D(3), respectively)- and the hydrophobic nature of vitamin D. The current state of 25(OH)D measurement is reviewed; modest differences between methodologies persist and confound the application of a single cut point (e.g., 30 ng/mL/75 nmol/L) for the diagnosis of low vitamin D status. The absence of standard calibrators contributes to between-laboratory differences in 25(OH)D measurement. Until there is improved assay standardization and subsequent evidence-based consensus, it seems premature to recommend widespread screening 25(OH)D measurement. Selectively obtaining 25(OH)D measurement in individuals at clinical risk for vitamin D deficiency and/or those most likely to promptly experience benefits from supplementation seems appropriate.
Binkley
Neil
N
Osteoporosis Clinical Center and Research Program, University of Wisconsin-Madison, Madison, WI 53705, USA. nbinkley@wisc.edu
Krueger
Diane
D
Lensmeyer
Gary
G
D002845:Chromatography / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D008403:Mass Screening / Q000379:methods; D009017:Morbidity / Q000639:trends; D015203:Reproducibility of Results; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology
D014807:Vitamin D; C104450:25-hydroxyvitamin D