Vitamin D helps regulate the amount of calcium and phosphate in the body. These nutrients are needed to keep bones, teeth and muscles healthy. Vitamin D deficiency occurs when the body doesn’t get enough vitamin D from sunlight or diet. Vitamin D deficiency can cause loss of bone density, osteoporosis, broken bones and rickets in children.

Vitamin D is sometimes called the sunshine vitamin because your body makes it from cholesterol when your body is exposed to sunlight.

Before your body can use vitamin D, your liver must change it into another form called 25 hydroxyvitamin D, or 25(OH)D. The Vitamin D Test measures the level of 25(OH)D in your blood in order to determine whether your body has deficient, insufficient, sufficient or excess levels of vitamin D in your blood to enable/prevent your body from working well.