Vit D
The most accurate measure of your vitamin D status.
What is it
25-hydroxyvitamin D is the storage form of vitamin D in the body and the standard marker for evaluating vitamin D status. It reflects intake from sun, food, and supplements over recent weeks.
Why it's measured
Vitamin D has been associated with bone health, immune function, mood, and a range of other outcomes in published research. Deficiency is common in modern populations.
Reference range
Standard laboratory reference
30 – 100 ng/mL
Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.
What results may indicate
Elevated
Very high values can warrant clinical evaluation. Most often reflects high-dose supplementation.
Lower
Has been associated with bone health concerns, reduced immune function, and mood changes in research literature.
These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.
When it's measured
Often measured annually or when deficiency is suspected.
Related markers
Measured in
A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.
Explore the Apex Panel →This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.