Journal Article

Role of Assay Type in Determining Free 25-Hydroxyvitamin D Levels in Diverse Populations

Bouillon, Roger, Lapidus, Jodi, Swanson, Christine M, Jacobs, Jon, Gao, Yuqian, Schoenmakers, Inez, Chun, Rene F, Wang, Ying, Jones, Kerry S, Smith, Richard D, Lee, Christine G, Adams, John S, Vanderschueren, Dirk, Hewison, Martin, Zmuda, Joseph M, Cauley, Jane A, Prentice, Ann, Orwoll, Eric S, Nielson, Carrie M, Pauwels, Steven, Shi, Tujin

2016

Overview

The choice of a vitamin D–binding protein assay is key in calculating free 25-hydroxyvitamin D levels. The results of this analysis support the use of total 25-hydroxyvitamin D as a marker of vitamin D status, regardless of race or GC genotype. To the Editor: It is unclear whether circulating free or bioavailable 25-hydroxyvitamin D is a better marker of vitamin D status than is total 25-hydroxyvitamin D, especially in racially diverse populations. Until recently, the only method to compare the levels was to estimate the level of free or bioavailable 25-hydroxyvitamin D from total 25-hydroxyvitamin D, vitamin D–binding protein (also known as gc-globulin, encoded by the GC gene), and albumin, with or without the GC genotype. Powe et al. reported that levels of vitamin D–binding protein, as measured on a monoclonal enzyme-linked immunosorbent assay (ELISA, R&D Systems), were lower in black . . .

• Publisher: Massachusetts Medical Society
• Subject: African Americans / Bioavailability / Black or African American / Blood Chemical Analysis - methods / Chromatography, Liquid / Environmental Molecular Sciences Laboratory / Enzyme-Linked Immunosorbent Assay / Genotypes / Humans / Male / Mass spectrometry / Polyclonal antibodies / Proteins / Race / Reference Values / Scientific imaging / Tandem Mass Spectrometry / Vitamin D / Vitamin D - analogs & derivatives / Vitamin D - blood / White People