This test is a measure of the levels of Vitamin D in the blood stream.
Vitamin D tests are used to determine if bone weakness, bone malformation, or abnormal metabolism of calcium (reflected by abnormal calcium, phosphorus or PTH tests) is occurring as a result of a deficiency or excess of vitamin D.
Vitamin D tests also may be used to help diagnose or monitor problems with parathyroid gland functioning since parathyroid hormone is essential for vitamin D activation. When vitamin D, calcium, phosphorus, or magnesium supplementation is necessary, vitamin D levels are sometimes measured to monitor treatment effectiveness.
Special Preparation: 8-12 Hour fast preferred for more accurate results, but not required.
More Detailed Vitamin D, 25 Hydroxy Test Information