25-hydroxyvitamin D is the primary circulating form of vitamin D and the most reliable indicator of vitamin D status in the body. This metabolite reflects total vitamin D input from sun exposure, dietary intake, and supplementation, with a half-life of approximately 2-3 weeks. Vitamin D undergoes hydroxylation in the liver to form 25-hydroxyvitamin D, which circulates bound to vitamin D binding protein. This metabolite serves as the substrate for production of the active hormone 1,25-dihydroxyvitamin D in the kidneys and other tissues, playing crucial roles in calcium homeostasis, bone health, and immune function.
25-hydroxyvitamin D is the primary circulating form of vitamin D and the standard measure of vitamin D status. It plays essential roles in calcium homeostasis, bone mineralization, immune modulation, and gene expression across multiple tissue types. Deficiency is widespread globally, including in otherwise healthy populations.
Levels below 20 ng/mL are classified as deficient; 20-29 ng/mL as insufficient (Endocrine Society criteria). Deficiency is associated with reduced bone mineral density, increased fracture risk, impaired immune function, and fatigue. Toxicity (typically >100 ng/mL) can cause hypercalcemia but is rare and almost exclusively due to supplementation.
Vitamin D receptors are expressed in skeletal muscle tissue, and adequate levels are linked to muscle contractility and neuromuscular function. Athletes training primarily indoors, at northern latitudes, or with limited sun exposure are at elevated risk for insufficiency. Seasonal variation in vitamin D levels is well-documented, with nadirs typically occurring in late winter.
Turnaround Time
3 days (up to 12 days)
Method
Immunochemiluminometric assay (ICMA). This assay is performed on the DiaSorin LIAISON® instrument in multiple laboratories throughout LabCorp. This highly automated test measures both D
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Choose your lab and check out. We send your lab requisition automatically — no doctor visit needed.
Get your sample collected
Visit a lab service center near you for a quick blood draw (or book at-home phlebotomy where available).
See your results
Your results land in your Insider portal, ready to review and act on — that easy.
Your price
$13.90$90
6.5× less than retail
Versus the typical direct-to-consumer retail price for this test (illustrative — consumer prices vary by provider and region).
$13.90
$24.97
$46.90
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25-hydroxyvitamin D is the primary circulating form of vitamin D and the most reliable indicator of vitamin D status in the body. This metabolite reflects total vitamin D input from sun exposure, dietary intake, and supplementation, with a half-life of approximately 2-3 weeks.
25-hydroxyvitamin D is the primary circulating form of vitamin D and the standard measure of vitamin D status. It plays essential roles in calcium homeostasis, bone mineralization, immune modulation, and gene expression across multiple tissue types.
Levels below 20 ng/mL are classified as deficient; 20-29 ng/mL as insufficient (Endocrine Society criteria). Deficiency is associated with reduced bone mineral density, increased fracture risk, impaired immune function, and fatigue.
The Vitamin D, 25-Hydroxy test starts at $13.90 at Labcorp, Quest, or BioReference. No doctor's visit and no insurance needed; we do not bill insurance. Fitomics Insider members pay from $12.90.
Results for the Vitamin D, 25-Hydroxy test are typically ready about 3 days after your draw, and up to 12 days for some samples. Your results land in your Insider portal.
No. When you order the Vitamin D, 25-Hydroxy test from Fitomics Research Labs, a licensed physician in our 50-state network reviews and signs your requisition after checkout, and it lands in your portal and inbox. Then visit any Labcorp, Quest, or BioReference patient service center for your draw; results post to your Insider portal.
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