Page 340 - Vitamin D and Cancer

Chapter 15
Assessment of Vitamin D Status
in the 21 Century
st

Bruce W. Hollis

Abstract The field of Vitamin D assay technology has progressed significantly over
the past 4 decades. Further, the clinical utility of these measurements has moved
from esoteric into mainstream clinical diagnosis. This movement has been fueled
by the realization that Vitamin D is involved in bodily systems beyond skeletal
integrity. The clinical assay techniques for circulating 25(OH)D and 1,25(OH) D
2
have progressed away from competitive protein-binding assay (CPBAs) that utilize
tritium reporters to radioimmunoassay (RIAs) that utilize both I125 and chemilu-
minescent reporters. These advances have allowed direct serum analysis of 25(OH)
D in an automated format that provides a huge sample throughput. Detection of
circulating 25(OH)D can also be achieved utilizing direct high-performance liquid
chromatographic (HPLC) or liquid chromatography coupled with mass spectrom-
etry (LC-MS) techniques. These methods are accurate, however, they require
expensive equipment and restrict sample throughput in the large clinical labora-
tory. Direct serum detection of 1,25(OH) D is unlikely to occur for many reasons
2
as a sample pre-purification will always be required. However, a semi-automated
chemiluminescent detection system with automated sample preparation is in final
development for the determination of circulating 1,25(OH) D. These advances will
2
allow both 25(OH)D and 1,25(OH) D to be detected in an accurate, rapid fashion
2
to meet the clinical demands we see emerging.

Keywords Vitamin D assay • 25-hydroxyvitamin D • 1,25-dihydroxyvitamin D

Disclosure Dr. Hollis is an academic consultant to the DiaSorin Corp.

B.W. Hollis (*)
Department of Pediatrics,
Darby Children’s Research Institute, Medical University of South Carolina,
173 Ashley Ave., Room 313, Charleston, SC 29425, USA
e-mail: holisb@musc.edu

D.L. Trump and C.S. Johnson (eds.), Vitamin D and Cancer, 327
DOI 10.1007/978-1-4419-7188-3_15, © Springer Science+Business Media, LLC 2011