Most Vitamin D is stored in the body tissues as the
25-hydroxyvitamin D derivative (25-OH-D). The biologically active
vitamin (1-alpha, 25-dihydroxyvitamin) D3 is produced locally in
various tissues where it modulates calcium absorption and
inflammatory responses. Total vitamin D nutritional status is
indicated by serum (25-OH-D) measurement.
Why should you measure Vitamin D?
- Detect toxicity: You can take too much, leading to vascular
calcification from hyperviatminosis D.
- Detect deficiency: Vitamin D regulates calcium and phosphorus
absorption/resorption to maintain bone health.
- Vitamin D deficiency and insufficiency were found quite
prevalent in a recent study of subjects with osteopenia or
osterporosis. Vitamin D deficiency was found among 33% of subjects
below 50 years of age and 31.1% of subjects over 50 years of age.
Vitamin D insufficiency was found among 35.9% of all
subjects.**
- Vitamin D insufficiency is linked to depression and Seasonal
Affective Disorder.
- Vitamin D is important in neurological autoimmune processes
like Multiple Sclerosis.
- Vitamin D upregulates apoptotic mechanisms in pro-inflammatory
cells to arrest appropriately and preventing on-going inflammation
that damages tissue.
- Recent studies have also linked low vitamin D levels with
higher risk of heart attack, various cancers, and autoimmune
diseases.
What form of Vitamin D are you measuring?
- Within hours, vitamin D from sunlight and diet is removed from
circulation and recirculates again a few hours later as (25-OH-D).
This form has the longest half life, about three weeks.
- (1, 25-OH)2D3)* is the more biologically active metabolite, but
plasma concentrations are mainly dependent on renal function,
appropriate parathyroid hormone levels, and the supply of calcium
and phosphate. The levels of this metabolic decline only after
vitamin depletion is virtually complete.
Vitamin D is also included in our
ION Profiles!
*In various publications the term, "vitamin
D3" has been used to identify the active form of vitamin D or its
precursors.
**Vitamin D status in patients with
osteopenia or osteoporosis - an audit of an endocrine clinic, "
Kocjan T, Tan TM, et al, Int J Vitam Nutr Res, 2006; 76(5):
307-13
Test name(s)
0032 - Vitamin D Assay
Description
Most vitamin D is stored in body tissues as the 25-hydroxyvitamin D derivative (25OHD). The biologically active vitamin (1-alpha, 25-dihydroxyvitamin D3) is produced locally in various tissues where it modulates calcium absorption and inflammatory responses. Total body vitamin D nutritional status is indicated by serum 25OHD measurement.
Method
Chemiluminescence
Turnaround time
5-7 days, 6 days average
Analytes
25-Hydroxyvitamin D