The National Institutes of Health (NIH) Office of Dietary Supplements (ODS) established the Vitamin D Standardization Program (VDSP) in November 2010. Part of the ODS Vitamin D Initiative, VDSP is an international collaborative effort to standardize the laboratory measurement of vitamin D status. A standardized laboratory measurement is one that is accurate and comparable over time, location, and laboratory procedure.
Serum total 25-hydroxyvitamin D [25(OH)D] concentration is used to assess an individual’s vitamin D status. Research has consistently shown that there is a great deal of variation in 25(OH)D assays. This assay variation impedes pooling of 25(OH)D results from different studies in systematic reviews for the specific purpose of determining dose-response and/or clinical cutpoints. The VDSP was established to correct this problem.
- VDSP Goal
To improve the detection, evaluation, and treatment of vitamin D deficiency and insufficiency by promoting the standardized laboratory measurement of serum total 25-hydroxyvitamin D [25(OH)D]. VDSP promotes the standardized laboratory measurement of total 25(OH)D (a measure of vitamin D status) to improve clinical and public health practice worldwide.
- VDSP Objectives
- Standardize vitamin D measurement in national health surveys worldwide.
- Promote standardized 25(OH)D measurement by assay manufacturers and clinical and research laboratories.
- Conduct an international research program devoted to 25(OH)D and its laboratory measurement.
- VDSP Participants
All VDSP programs are open to assay manufacturers, clinical and commercial laboratories, national survey laboratories, and research laboratories.
Standardized Laboratory Measurement of Total 25(OH)D
A standardized laboratory measurement of 25(OH)D is one that is accurate and comparable to the NIST
and Ghent Reference Measurement Procedures (RMPs)
over time, location, and laboratory procedure. There are four basic steps necessary to achieve standardization. more
VDSP Reference Measurement System (RMS) Specifics
VDSP developed an RMS to establish the world-wide standardization of 25-hydroxyvitamin D [25(OH)D] measurements. The RMS includes measurent procedures, standard reference materials, CDC certification and/or accuracy-based quality assurance programs, and study designs for standardizing completed studies. more
Commutability is defined as the equivalence of mathematical relationships between results obtained using different measurement procedures for representative samples. The VDSP conducts ongoing commutability studies to establish that the Standardized Reference Materials® (SRMs), and the materials used in accuracy-based performance testing/external quality assessment programs are commutable. more
Resources and References
A growing number of publications relevant to the VDSP are available. more
Key Collaborating Organizations
Current VDSP collaborators and participating national health and nutrition surveys. more
VDSP News is a free electronic publication that provides updates on the activities of the VDSP and related information. more
A public meeting to showcase the VDSP’s progress was held on the National Institute of Standards and Technology campus on November 14, 2013. more
Christopher T. Sempos, Ph.D.
Program Coordinator, Vitamin D Standardization Program
NIH Office of Dietary Supplements