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Paediatric Laboratory Medicine

Vitamin D2 and D3, Blood

Clinical Significance

Vitamin D is a fat-soluble steroid prohormone mainly produced photochemically in the skin from 7-dehydrocholesterol. Two forms of vitamin D are biologically relevant – vitamin D3 (Cholecalciferol) and vitamin D2 (Ergocalciferol). Epidemiological studies have shown a high global prevalence of vitamin D insufficiency and deficiency. The measurement of vitamin D status provides opportunities for preventive and therapeutic interventions. Vitamin D deficiency is a cause of secondary hyperparathyroidism and diseases resulting in impaired bone metabolism (like rickets, osteoporosis, osteomalacia). Reduced 25-OH vitamin D concentrations in blood (vitamin D insufficiency) have been associated with an increasing risk of many chronic diseases, including common cancers, autoimmune or infectious diseases or cardiovascular problems.

Test Name

Vitamin D2 and D3, Blood

Test Code



Biochemistry - Biochemistry



External Proficiency Testing


Turn Around Time


Specimen Type

Serum, Sodium/Lithium Heparin 

Minimum Specimen Requirements

250 uL



Approval is not required

CPT Codes


Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Phone: 416-813-7200
Phone: 1-855-381-3212

Reference Range

Optimal range: 70 - 250 nmol/L
Range reflects the summer months only.
The winter range is slightly lower.

Toxic: >250 nmol/L
Optimal: >70 nmol/L
Adequate: 50-70 nmol/L
Sub-Optimal: 35-50 nmol/L
Deficient: <35 nmol/L