Vitamin D Total Test

Vitamin D is a family of compounds that is essential for the proper growth and formation of teeth and bones. Two forms of vitamin D can be measured in the blood, 25-hydroxyvitamin D and 1,25-dihydroxy vitamin D. The 25-hydroxyvitamin D is the major form in the blood and is the relatively inactive precursor to the active hormone, 1,25-dihydroxy vitamin D. Because of its long half-life and higher concentrations 25-hydroxyvitamin D is commonly measured to assess and monitor vitamin D status in individuals. The main role of Vitamin D is to help regulate blood levels of calcium, phosphorus, and magnesium. Vitamin D is vital for the growth and health of bone; without it, bones will be soft, malformed, and unable to repair themselves normally, resulting in diseases called rickets in children and osteomalacia in adults. Vitamin D has also been shown to influence the growth and differentiation of many other tissues and to help regulate the immune system. These other functions have implicated vitamin D in other disorders, such as autoimmunity and cancer.

People at higher risk of deficiency include the elderly or obese people, people who don't get adequate sun exposure. Adequate sun exposure is estimated to be two periods per week of 5-20 minutes. People who do not have adequate sun exposure may obtain the vitamin D that they need from food sources or supplements.