Vitamin D Test – Comprehensive Assessment of Vitamin D2 and D3 Levels

The Vitamin D Test from Mosaic Diagnostics Laboratory provides a precise measurement of 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3, the two main circulating forms of vitamin D in the body. This test can be performed using either serum or dried blood spot (DBS) collection and is considered the gold standard for evaluating true vitamin D status.

Because 25-hydroxyvitamin D is the major storage form of vitamin D, it serves as the most accurate indicator of overall vitamin D sufficiency—reflecting both dietary intake and sunlight exposure.

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THE ROLE OF VITAMIN D IN HEALTH

Vitamin D plays a vital role in calcium and phosphorus regulation, supporting bone growth, strength, and mineralization. However, research has shown that vitamin D’s influence extends far beyond bone health. It helps regulate the expression of over 2,000 genes involved in:

• Cell growth and differentiation

• Immune system modulation

• Inflammation control

• Neurological function and mood regulation

Vitamin D acts as a hormone-like messenger that affects nearly every cell in the body. Adequate levels are crucial for maintaining strong bones, optimal immune function, cardiovascular health, and mental well-being.

VITAMIN D DEFICIENCY AND HEALTH RISKS

Vitamin D deficiency is a global health concern and is linked to an increased risk of numerous chronic diseases and conditions, including:

• Cardiovascular disease (including hypertension and stroke)

• Osteoporosis and osteomalacia

• Type I and Type II diabetes

• Cancers (especially prostate, breast, and colon)

• Autoimmune diseases (including multiple sclerosis and rheumatoid arthritis)

• Chronic fatigue and fibromyalgia

• Inflammatory bowel disease (IBD)

• Mood and psychiatric disorders (depression, anxiety, schizophrenia)

• Cognitive decline and memory impairment in seniors

• Birth defects related to maternal deficiency

Deficiency is particularly common among:

• Infants who are exclusively breastfed without supplementation

• Older adults or those who are homebound

• Individuals with darker skin pigmentation (higher melanin reduces vitamin D synthesis)

• People who avoid sunlight or use constant sun protection

• Those with malabsorption, liver disease, or obesity

SUNLIGHT, DIET, AND SUPPLEMENTATION

Sunlight exposure triggers vitamin D production in the skin. However, modern indoor lifestyles, sunscreen use, and seasonal variation often result in inadequate synthesis—especially during winter months.

Dietary sources of natural vitamin D are limited, found mainly in fatty fish, fish liver oils, and eggs. Many foods are fortified with synthetic vitamin D, though these forms may be less bioavailable and shorter-lasting in the body.

The Vitamin D Test helps determine whether sun exposure, dietary intake, or supplementation are sufficient, and whether additional support may be needed to optimize vitamin D status and overall health.

RECOMMENDED FOR INDIVIDUALS WITH:

• Cardiovascular disease or hypertension

• Osteoporosis or bone pain

• Diabetes (Type I or II)

• Chronic fatigue or muscle weakness

• Autoimmune or inflammatory disorders

• Mood changes, depression, or seasonal affective disorder

• Cognitive decline or memory issues

• Infertility or pregnancy complications

• Cancer prevention or monitoring

• Low calcium or chronic joint pain

INCLUDES

✅ Laboratory Test
✅ Doctor’s Detailed Review of Test Results
✅ Personalized Doctor’s Recommendations and Action Plan

Important: This test is not available to residents of New York. Orders placed from New York will be automatically canceled, and any submitted samples will be discarded.