ADVIA Centaur Vitamin D Total Assay
Siemens Healthcare Diagnostics offers a fully equimolar, automated total 25(OH)vitamin D (~100% D2 and D3) assay employing a proprietary monoclonal with minimal 1.1% 3-epi-25(OH)vitamin D3 cross-reactivity aligned to the ID-LC/MS/MS 25(OH)vitamin D Reference Measurement Procedure (RMP)2-3, the reference procedure for the Vitamin D Standardization Program (VDSP). Laboratories can meet increased testing demands by consolidating vitamin D testing on a fully automated, high-throughput immunoassay system.
- Confidence in results through alignment to the 25(OH)vitamin D RMP2-3
- Certified procedure of the CDC Vitamin D Standardization-Certification Program (VDSCP)1
- Consistent and clinically accurate patient results with the equimolar total measurement of 25(OH)vitamin D2 and D3
- Vitamin D can be combined with routine, stat, and specialty assays without compromising time – results are provided in 18 minutes with a throughput of 240 tests per hour
- Proprietary monoclonal antibody provides lot-to-lot consistency
- Reduced risk of confounding assessment with minimal cross-reactivity with 3-epi-25(OH)vitamin D3(1.1%)
- A broad dynamic assay range (4.2–150 ng/mL) and on-board dilution – accommodates variety of patient results with minimal intervention.
- Total measurement of 25(OH)vitamin D2 and D3
- Good precision – 4.2% - 11.9% CV
- Traceable to the ID-LC/MS/MS 25(OH)vitamin D RMP
- Results in as little as 18 minutes (ADVIA Centaur® XP)
Vitamin D Assay Specifications
Vitamin D Standardization
Why Are Standardized Reference Materials Important?
Standardization of reference materials for in vitro diagnostic tests helps to harmonize results across test manufacturers and methods to improve the diagnosis, treatment, and prevention of disease. Reference standards serve as an anchor that can provide comparability across time and methods. Developing reference standards for assays is not a universal or easy procedure; success of any international reference material depends on that material being commutable across all manufacturers and methods.
Impact of the Lack of Standardization for Vitamin D
Without an internationally recognized, commutable vitamin D reference material, biases in slopes across methods and manufacturers can be observed. Scatter is apparent in assay comparisons between manufacturers as well as between laboratory-developed LC/MS/MS assays; this scatter may be due to differences in the way the different manufacturers’ systems measure vitamin D, varying vitamin D releasing processes, and heterophilic interferences.
Vitamin D standardization is necessary to create the anchor vitamin D values need, and it is important that laboratories and clinicians know how their vitamin D assay is standardized.
The Vitamin D Standardization Program (VDSP)
VDSP is an initiative of the NIH Office of Dietary Supplements (NIH ODS) and a collaboration with the National Institute of Standards and Technology (NIST), the CDC, and Ghent University.
- VDSP, under the coordination of Christopher Sempos, PhD, NIH ODS, aims to standardize 25(OH)vitamin D measurement across methods and manufacturers.
- The NIST Reference Measurement Procedure (RMP) is the primary reference method for the measurement of total 25(OH)vitamin D. This method separates out the 3-epi-25(OH)vitamin D3 from the 25(OH)vitamin D3, ensuring that the 25(OH)vitamin D3 is not overestimated.
- A second method by Prof. Linda Thienpont, Ghent University, is also available. It is an ID-LC/MS/MS method for vitamin D in human serum that is traceable to NIST Standard SRM2972.4
CDC Hormone Standardization Program (HoSt)
Ongoing manufacturer certification for vitamin D standardization will be part of the CDC HoSt program, conducted by the CDC’s Clinical Chemistry Branch, Division of Laboratory Services, under the supervision of Hubert W. Vesper, PhD, Director, Clinical Standardization Programs, and Chief, Protein Biomarker Biomarker and Lipid Reference Laboratory. Previous HoSt program assays include testosterone and estradiol.
The CDC Standardization Program for vitamin D is a two-phase process:
- First, assay manufacturers submit initial sample results for calibration to the standard.
- Manufacturers then receive quarterly blinded challenges to verify and monitor stability of calibration over time.
- The performance criteria are a mean bias of 5% and imprecision of 10%.
- After participants pass four consecutive surveys, they are awarded a certification for a year.5 Renewal is an annual process.
Assay availability may vary from country to country and is subject to local regulatory requirements.
1CDC Vitamin D Standardization-Certification Program (VDSCP)—Total 25hydroxy Vitamin D Certified Procedures; 2017 Mar [cited 2017 Jun]. Available from: https://www.cdc.gov/labstandards/pdf/hs/CDC_Certified_Vitamin_D_Procedures.pdf
2Sempos CT, Vesper HW, Phinney KW, Thienpont LM, Coates PM, Vitamin D Standardization Program (VDSP.) Vitamin D status as an international issue: National surveys and the problem of standardization. Scandinavian Journal of Clinical & Laboratory Investigation, 2012; 72(Suppl 243): 32 -40
3Thienpont L, Stepman HCM, Vesper HW. Standardization of measurements of 25-Hydroxyvitamin D3 and D2. Scandinavian Journal of Clinical & Laboratory Investigation, 2012; 72(Suppl 243): 41 -49
4Scand J Clin Lab Invest. 2012;72(Suppl 243):41-49. 2