Medically reviewed by Soma Mandal, MD A vitamin D test is a blood test that measures the level of vitamin D (calciferol) in ...

“Vitamin D deficiency is very common and ongoing research ... showed 14% lower circulating concentrations of vitamin D (25-hydroxyvitamin D, a form of vitamin D) than those not diagnosed with ...

Despite the importance of vitamin D for overall health, it is estimated that about one billion people worldwide have a deficiency, usually defined as having serum levels of 25-hydroxyvitamin D 3 ...

According to the International Osteoporosis Foundation, osteoporosis is the most common bone disease. It affects one in five ...