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VITAMIN D, DEFICIENCY SCREEN (25-HYDROXY)
MessageChemistry
Test Code
LAB535
Alias/See Also
25-Hydroxy Vitamin D, Vitamin D
CPT Codes
82306
Includes
25-Hydroxy Vitamin D
Preferred Specimen
Gold top (serum separator tube)
Minimum Volume
Whole blood: 700 uL (TWO full red-top microtainers).
Serum: 400 uL
Serum: 400 uL
Other Acceptable Specimens
Red Top Acceptable
Specimen Stability
Ambient: <1 day
Refrigerated: 7 days
Frozen: 4 weeks
Refrigerated: 7 days
Frozen: 4 weeks
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolyzed specimens
Methodology
Chemiluminescence
FDA Status
Approved
Setup Schedule
Daily
Report Available
Same day
Reference Range
| Deficient: | <19 ng/mL |
| Sufficient: | 20-50 ng/mL |
| Risk of Hypercalciuria: | >50 ng/mL |
| Risk of Toxicity: | >80 ng/mL |
Clinical Significance
Vitamin D is a fat soluble steroid hormone that comes in two forms, vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D metabolites are bound to a vitamin D binding protein and are circulated throughout the body. The concentration of 1,25-(OH)2 Vitamin D is 1000 times lower than 25-OH Vitamin D and has a half life of 4 hours. Due to its half life of 2–3 weeks, 25-OH Vitamin D is the metabolite that is the most reliable clinical indicator of vitamin D status. Also, 25-OH Vitamin D levels are indicative of the body’s storage levels of vitamin D and correlate with the clinical symptoms of vitamin D deficiency. The active form, 1,25-(OH)2 Vitamin D, increases the intestinal absorption of calcium and phosphorous, both are required for regulating bone metabolism. Research has indicated that vitamin D deficiency may be linked to chronic diseases such as cancer (breast, colon and prostate), cardiovascular disease, osteoporosis, osteomalacia and several autoimmune diseases among others.
Performing Laboratory
Hoag Newport
