vitamin D measurementGo to external page http://www.ebi.ac.uk/efo/EFO_0004631
A quantification of Vitamin D levels, typically in blood. Vitamin D includes both CHOLECALCIFEROLS and ERGOCALCIFEROLS, which have the common effect of preventing or curing RICKETS in animals. It can also be viewed as a hormone since it can be formed in SKIN by action of ULTRAVIOLET RAYS upon the precursors, 7-dehydrocholesterol and ERGOSTEROL, and acts on VITAMIN D RECEPTORS to regulate CALCIUM in opposition to PARATHYROID HORMONE (MeSH). 25-hydroxyvitamin D or calcifediol, a prehormone precursor of vitamin D, is widely used as a proxy to quanitfy vitamin D levels in blood.