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Vitamin D, 1, 25 Dihydroxy, plasma or serum

Alternate test name

Calcitriol; Vitamin D; 1,25-Dihydroxy Vitamin D; 1,25-Dihydroxycholecalciferol; 1,25-Dihydroxyvitamin D3

Lab area
Clinical Biochemistry - General
Method and equipment

Method: Chemiluminescence immunoassay

Equipment: Diasorin Liaison XL

Expected turn-around time
7 days (excluding weekends and holidays)
Specimen type

Serum, or plasma (heparinized)

Specimen requirements

0.5 mL

Storage and transportation
  • Separate serum or plasma from cells as quickly as possible after collection.
  • Ship frozen.
  • Avoid freeze/thaw cycles.
Shipping information
The Hospital for Sick Children
Rapid Response Laboratory
555 University Avenue, Room 3642
Toronto, ON
M5G 1X8
Phone: 416-813-7200
Toll Free: 1-855-381-3212
Hours: 7 days/week, 24 hours/day
Disease condition

The 1,25-Dihydroxyvitamin D (1,25-Vit D) test may be requested for the following conditions:

  • Unexplained hypercalcemia, particularly if PTH is low (or inappropriately normal), such as if hypercalcemia occurs with sarcoidosis or cancer  
  • To help in the diagnosis and treatment of rickets, in the case of deficient renal conversion of 25-Hydroxyvitamin D to 1,25-Vit D (Rickets Type I) or deficient response (Rickets Type II).
  • To monitor the renal endocrine reserve for 1,25-Vit D production in patients with primary kidney disease and secondary hyperparathyroidism.
  • In the diagnosis and monitoring of various forms of hypoparathyroidism
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