Clinical Information

1,25-Dihydroxy vitamin D is the active form of vitamin D and is produced primarily in the kidney. Its measurement may be useful in the:

• Assessment of vitamin D status in patients with significant kidney disease.
• Differential diagnosis of hypercalcemia when the cause is not clear.
• As part of the workup to evaluate a patient for possible metabolic bone disease.
• Investigation of selected patients with vitamin D deficiency when the cause is unclear and/or inherited disorder is suspected (e.g., end-organ resistance to 1,25-dihydroxy vitamin D.

This test should NOT be used as an initial screen for vitamin D deficiency nor to assess vitamin D toxicity. Vitamin D, 25 Hydroxy is the appropriate test for initial assessment of vitamin D stores.