Vitamin D, 25-Hydroxy
The Vitamin D 25-Hydroxy Blood Test is often ordered for individuals that have symptoms of vitamin D deficiency. It may also be ordered before an individual begins osteoporosis drug therapy. Low levels may indicate a dietary deficiency, mal-absorption or lack of exposure to sunlight.
Who should test?
- Vitamin D is clinically useful to diagnose disorders related
- to intestinal malabsorption and vitamin D deficiency or
- intoxication. The 25-Hydroxy vitamin D blood test allows
- monitoring for therapeutic response in patients being
- treated for vitamin D-related disorders.
The body gets vitamin D from two sources: dietary intake through foods and supplements (exogenous), and through production in the skin upon exposure to sunlight (endogenous). Although vitamin D is found naturally in only a few foods, in the United States, many products are supplemented with it, including milk, breakfast cereals and juices. Those at risk of vitamin D deficiency include individuals who are elderly; obese; have dark skin; are institutionalized, home bound or have limited sun exposure; have undergone gastric bypass surgery; and have conditions such as cystic fibrosis and Crohn's disease that interfere with fat absorption.