25-Hydroxyvitamin D, known for its role in bone health and calcium absorption, also appears to affect immune function, neurodegenerative and cardiovascular issues, and other conditions. Vitamin D occurs in two forms—D3 is obtained from animal diet sources and through sun exposure, and D2 is obtained through vegetable diet sources. Both forms of the vitamin are used to fortify various foods and in supplements. Doctor's Data uses the gold standard LC/MS QQQ method to measure Vitamin D2, D3 and total Vitamin D. 
Useful for:
Alzheimer's Disease
Bone Health
Calcium Absorption
Cardiovascular Disease
Depression
Immune Function
Infections
Multiple Sclerosis
Neurocognitive Dysfunction
Preeclampsia
Rheumatoid Arthritis
Type 2 Diabetes