Vitamin D

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Also known as: Ergocalciferol (vitamin D2); Cholecalciferol (vitamin D3); Calcidiol (25-hydroxyvitamin D [25(OH)D]); Calcifidiol (25-hydroxy-vitamin D); Calcitriol (1,25 dihydroxyvitamin D [1,25(OH)(2)D])
Formal name: 25-hydroxy-vitamin D (Calcidiol); 1,25 dihydroxy-vitamin D (Calcitriol)

At a Glance

Why Get Tested?

To investigate a problem related to bone metabolism or parathyroid function, possible vitamin D deficiency, malabsorption and to monitor some patients taking vitamin D.

When to Get Tested?

Your doctor may request a vitamin D measurement in the following situations:

  • If you are found to have an abnormal calcium, phosphate, and/or parathyroid hormone¬†(PTH) concentration in the blood.
  • As part of the investigation of some forms of bone disease or muscle weakness/pain.
  • If you have disease of the gastrointestinal tract that could result in malabsorption.
  • If you are receiving certain anticonvulsant drugs.

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

None required