Synonyms: Cholecalciferol Metabolite; 25-Hydroxycalciferol; 25-OH-D; Vitamin D3 Metabolite
Why It Is Done
Determine if a patient has a deficiency or excess of vitamin D.
Test Overview
25 hydroxy vitamin D is the most accurate measure of vitamin D stores in the body.
25 hydroxy vitamin D is stored in the liver where it is converted from other forms of vitamin D, either obtained from the diet or made in the skin by sunlight.
25 hydroxy vitamin D is then changed to its active form, 1,25 dihydroxy vitamin D in the kidney. This active form of vitamin D causes increases in calcium and phosphate by activity primarily on the intestines, kidney and bone.
How To Prepare
No special preparation needed.