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Vitamin D, total (25-hydroxy vitamin D)
(a.k.a 25OH Vit D, Vit D, Total Vitamin D)
minimum sample volume required ~ 5ml
Test Code: TVD
Tube type: SST
Special instructions
None
Interpretation
Please refer to interpretative comments and thresholds on individual reports.
More information can be found in the RUH clinical guideline for primary care: Vitamin D deficiency in Adults.
Minimum retesting interval
Test should not be repeated within 60 days
Reference range
>50
Units
nmol/L
Turnaround Time
2
days
Department: Biochemistry
Clinical Application
Vitamin D is essential for regulating the absorption of calcium and phosphate from the gut, for the growth and maintenance of strong bones and for musculoskeletal health. The major circulating form of vitamin D is 25-hydroxyvitamin D and this is the form that is routinely measured in the laboratory.
Routine screening of vitamin D is not recommended in asymptomatic individuals.
Individuals who are asymptomatic but have risk factors should be advised to consider supplements as per the Department of Health document: Vitamin D - Advice on Supplements for at risk groups (2012)
Monitoring of nutritional supplementation is not required.
Monitoring of high dose therapy should be done >3 months after replacement to assess response; however, calcium levels should be checked after one month and more frequently if significant renal impairment is present.
Webpage updated: December 2024
