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Vitamin D, 25-Hydroxy
|Performed by||Parnassus Chemistry|
|In House Availability||Test performed daily 0800-2400|
|Method||Beckman Coulter DxI600 Chemiluminescent Immunoassay|
|Container type||Gold top|
|Amount to Collect||3 mL blood|
|Preferred volume||1.5 mL serum|
|Min. Volume||0.5 mL serum|
|Processing notes||Refrigerate serum aliquot|
|Normal range||20 - 50 ng/mL
25-OHD values < 20 are considered to be insufficient and values < 10 - 12 are associated with vitamin D deficiency and risk for osteomalacia. Although values of 20 or more are generally considered to be sufficient, values in the range of 20 - 30 may be insufficient in certain high risk patient subgroups. There is no known benefit of values > 50, and values > 100 should be avoided because of possible risk of vitamin D toxicity.
|Synonyms||25-Hydroxycalciferol; 25-OH-D; Cholecalciferol Metabolite|
|Stability||After separation from cells serum is stable at room temperature for 3 days, refrigerated 1 week and frozen at -20C 6 months.|
|Additional information||To convert µg/L to nmol/L (SI units) multiply by 2.496.
Normal range cutoffs for screening are based on the Institute of Medicine (IOM) Committee's 2011 Report on Dietary Reference Intakes for Calcium and Vitamin D. For a discussion of the controversy regarding normal range cutoffs and the IOM recommendations, see Rosen C, et al. J Clin Endocrinol Metab 97: 1146–1152, 2012.
|Last Updated||5/24/2016 14:11:47|
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