What is 25-Hydroxy Vitamin D?
25-hydroxy vitamin D is the inactive form of vitamin D. This test tells doctors, with the most accuracy, how much vitamin D is currently in the body. 25-Hydroxy vitamin D and 1, 25 dihydroxy-vitamin D levels are not the same as 25-hydroxy is before activation and 1, 25 dihydroxy is after activation. Patients with little to no sunlight exposure, liver disease, kidney disease or restricted dietary intake of foods that contain vitamin D will have lower 25-hydroxy levels. Malabsorption disorders may affect vitamin D levels, along with levels of other vitamins.

High levels of vitamin D in blood are rare, but one condition – hypervitaminosis D.

Normal Value Range

  • Negative Pregnancy Adult: 14 to 80 ng/mL or 35 to 200 nmol/L
  • Pregnancy Trimester One: 18 to 27 ng/mL or 45 to 67 nmol/L
  • Pregnancy Trimester Two: 10 to 22 ng/mL or 25 to 55 nmol/L
  • Pregnancy Trimester Three: 10 to 18 ng/mL or 25 to 45 nmol/L
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