Standardization and Certification of the ADVIA Centaur Vitamin D Total Assay

Background:  In recent years, the Siemens ADVIA Centaur® Vitamin D Total assay was standardized for traceability to the National Institute of Standardization and Technology (NIST)-Ghent reference method procedure (RMP) used in the Vitamin D Standardization Program (VDSP). Here, we compare results from the newer ADVIA Centaur Vitamin D assay to results obtained using several methods traceable to the VDSP NIST-Ghent RMP. We also present results of successful participation in the Centers for Disease Control and Prevention (CDC) vitamin D certification program (VDSCP).Methods: The ADVIA Centaur Vitamin D Total assay results were compared to values assigned at Ghent University (n = 122); values assigned by methods metrologically traceable to the VDSP NIST-Ghent RMP (n = 177); RMP-assigned values by the College of American Pathologists (CAP) and Vitamin D External Quality Assessment Scheme (DEQAS) survey (n = 30); and to a third-party VDSCP-certified assay    (n = 149). The CDC certification scheme (VDSCP), which requires annual certification, was applied over four consecutive years (2013–2017).Results: Correlation between the standardized ADVIA Centaur Vitamin D Total assay and the VDSP NIST-Ghent RMP results was 99%; bias was –0.09%. Bias in comparison to CAP and DEQAS samples was < 25% for 96% of samples. Bias for CDC VDSCP certification samples was 0.3%, mean CV was 5.5%. Correlation to the Esoterix CDC VDSCP-certified ID-LC/MS/MS method was 95% for vitamin D total and 97% for samples containing only 25(OH)D3.Conclusions: The ADVIA Centaur Vitamin D Total assay traceable to the VDSP NIST-Ghent RMP demonstrated good performance and is acceptable for clinical use based on imprecision, and by comparison to CAP and DEQAS surveys. The assay is aligned to the VDSP NIST-Ghent RMP, and was among the first automated immunoassays certified by the CDC VDSCP. As of February 2017, the assay has achieved VDSCP certification for four consecutive years.