Because Canada is located above the 35° North latitude, the average Canadian’s exposure to sunlight is insufficient to maintain adequate Vitamin D levels, especially during the winter. Therefore, measuring serum 25-hydroxyvitamin D levels is not necessary because routine supplementation with Vitamin D is appropriate for the general population. An exception is made for measuring Vitamin D levels in patients with significant renal or metabolic disease.
Sources:
British Columbia Guidelines and Protocol Advisory Committee. Vitamin D testing protocol [Internet]. 2013 Jun 1 [cited 2014 Sep 25].
Hanley DA, et al. Vitamin D in adult health and disease: a review and guideline statement from Osteoporosis Canada. CMAJ. Sep 7 2010;182(12):E610-618. PMID: 20624868.
Ontario Association of Medical Laboratories. Guideline for the Appropriate Ordering of Serum Tests for 25-hydroxy Vitamin D and 1,25-dihydroxy Vitamin D [Internet]. 2010 Jun [cited 2014 Sep 25].
Toward Optimized Practice (TOP) Working Group for Vitamin D. Guideline for Vitamin D Testing and Supplementation in Adults [Internet]. Edmonton (AB): Toward Optimized Practice; 2012 Oct 31 [cited 2014 Sep 25].
Related Resources:
Patient Pamphlet: Vitamin D Tests: When you need them and when you don’t