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International Journal of Endocrinology
Volume 2014, Article ID 691679, 12 pages
http://dx.doi.org/10.1155/2014/691679
Research Article

Influence of Vitamin D Binding Protein on Accuracy of 25-Hydroxyvitamin D Measurement Using the ADVIA Centaur Vitamin D Total Assay

Siemens Healthcare Diagnostics, 511 Benedict Avenue, Tarrytown, NY 10591, USA

Received 13 December 2013; Revised 7 April 2014; Accepted 28 April 2014; Published 19 June 2014

Academic Editor: Arthur Santora

Copyright © 2014 James Freeman et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Vitamin D status in different populations relies on accurate measurement of total serum 25-hydroxyvitamin D [25(OH)D] concentrations [i.e., 25(OH)D3 and 25(OH)D2]. This study evaluated agreement between the ADVIA Centaur Vitamin D Total assay for 25(OH)D testing (traceable to the NIST-Ghent reference method procedure) and a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for various populations with different levels of vitamin D binding protein (DBP). Total serum 25(OH)D concentrations were measured for 36 pregnant women, 40 hemodialysis patients, and 30 samples (DBP-spiked or not) from healthy subjects. ELISA measured DBP levels. The mean serum DBP concentrations were higher for pregnancy (415 μg/mL) and lower for hemodialysis subjects (198 μg/mL) than for healthy subjects and were highest for spiked serum (545 μg/mL). The average bias between the ADVIA Centaur assay and the LC-MS/MS method was −1.4% (healthy), −6.1% (pregnancy), and 4.4% (hemodialysis). The slightly greater bias for samples from some pregnancy and hemodialysis subjects with serum DBP levels outside of the normal healthy range fell within a clinically acceptable range—reflected by analysis of their low-range (≤136 μg/mL), medium-range (137–559 μg/mL), and high-range (≥560 μg/mL) DBP groups. Thus, the ADVIA Centaur Vitamin D Total assay demonstrates acceptable performance compared with an LC-MS/MS method for populations containing different amounts of DBP.