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Laboratory: Clinical Biochemistry  (SPECIAL CHEMISTRY)
Test Name:
Test Code: VD25
Clinical Information:
Test Indications: Screening for vitamin D deficiency in healthy individuals is not recommended.
25-OH vitamin D should only be ordered in the following clinical conditions:
- Metabolic bone disease (recurrent fractures, rickets, osteomalacia, osteopenia, osteoporosis).
- Abnormal blood calcium, magnesium, or phosphate concentrations.
- Parathyroid disease
- Malabsorption syndrome (celiacs disease, cystic fibrosis, small bowel surgery, medications that interfere with vitamin D absorption such as cholestyramine, orlistat, etc).
- Anticonvulsant agents.
- Chronic renal disease.
- Chronic liver disease.
- Intake of high doses of vitamin D combined with symptoms suggestive of hypervitaminosis D
Collection Devices:
Alternate Device: Serum Separator (SST) Tube(s) - Full Tube Collection
Plasma is not acceptable. 
Specimen Required:

Serum: 0.5 mL
Pediatric Serum: 0.25 mL

Special Processing: Spin down and separate serum within 1 hour of collection.
Specimen Stability: 
Ambient: 72 hours
Refrigerated: 5 days
Frozen: 6 months

Specimen Type: Serum
Shipping & Storage: Store and ship frozen. 
Testing Laboratory (MB): 
MS5-Health Science Centre
Reference Values:
Category Result (nmol/L)
Potentially harmful:
27 – 74
75 – 249
≥ 250

Method of Analysis: DiaSorin Liaison XL chemiluminescent competitive immunoassay (effective August 8, 2023) 

Reference Value Document Links: Osteoporosis Canada Recommendations
- Hanley DA, Cranney A, Jones G, Whiting SJ, Leslie WD; Guidelines Committee of the Scientific Advisory Council of Osteoporosis Canada. Vitamin D in adult health and disease: a review and guideline statement from Osteoporosis Canada (summary). CMAJ. 2010 Sep 7;182(12):1315-9. doi: 10.1503/cmaj.091062.

Within 1 Week
See Also:
More Information:
Interpretation & Assay Interferences: 
Steroid % Cross-reactivity
25 OH Vitamin D2 100.00%
25 OH Vitamin D3 100.00%
Vitamin D2 1.90%
Vitamin D3 1.90%
1,25-(OH)2 Vitamin D2 6.70%
1,25-(OH)2 Vitamin D3 9.30%
3-epi-25 OH Vitamin D3 1.30%
Current methodology is suitable for testing in children less than 1 year old. Non-biologically active 3-epimer present in significant quantities in young children does not interfere with current assay.