Laboratory: | Clinical Biochemistry | ||||
Test Name: |
VITAMIN D (1,25-DIHYDROXY) - (S)
Test Code:
D125
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Clinical Information: |
THIS TEST IS ONLY AVAILABLE TO ENDOCRINOLOGIST AND NEPHROLOGIST. ALL OTHER REQUESTS MUST BE APPROVED BY A CLINICAL BIOCHEMIST USING THE DESIGNATED TEST APPROVAL FORM.
Screening for vitamin D deficiency in healthy individuals is not recommended. This test is not appropriate for diagnosing vitamin D deficiency or insufficiency. 1,25-OH vitamin D should only be ordered in the following clinical conditions: 1. Clinical evidence of vitamin D deficiency due to hereditary deficiency of renal 1-alpha hydroxylase or end-organ resistance to 1,25-dihydroxy vitamin D. 2. Hypercalcemia or renal failure in addition to Vitamin D, 25-Hydroxy testing. No special patient preparation required. |
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Collection Devices: |
Serum GEL tube is not acceptable. Lithium Heparin No Gel tube is acceptable.
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Specimen Required: |
Serum: 2.0 mL
Pediatric Serum: 1.0 mL
Serum: 2.0 mL
Note that minimum volume does not allow for repeat analysis. |
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Referral: |
Serum collected WITHOUT separator gel in aliquot tube shipped in on ice.
Adult: minimum 2.0 mL Pediatric : minimum 1.0 mL Spin down and separate serum. Store and ship serum frozen. |
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Requisition: | |||||
Reference Values: |
Reference values will be given with report.
Complete details of the reference values are available at In-Common Laboratories Reference Values http://www.hicl.on.ca/search_tcna.asp?TCString=125VITD |
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Availability: |
Within 2 Weeks
This test is a referral to In-Common Labs, Ontario. All requests from physicians other than Endocrinologist & Nephrologist must be approved by a Clinical Biochemist before lab send out.
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See Also: | |||||
More Information: |
Serum collected WITHOUT separator gel in aliquot tube shipped in on ice. Store and ship serum frozen.
Spin down and separate serum. References: 1. Choosing Wisely: Don’t routinely measure 1,25-dihydroxyvitamin D unless the patient has hypercalcemia or decreased kidney function. http://www.choosingwisely.org/clinician-lists/endocrine-society-vitamin-d-testing/ 2. Bringhurst FR, Demay MB, Kronenberg HM: Vitamin D (calciferols): metabolism of vitamin D. In Williams Textbook of Endocrinology. Ninth edition. Edited by JD Wilson, DW Foster, HM Kronenberg, PR Larsen. Philadelphia, WB Saunders Company, 1998, pp 1166-1169. 3. Bikle D, Adams J, Christakos S. Primer on the metabolic bone diseases and disorders of mineral metabolism. Washington: American Society for Bone and Mineral Research. c2008.Chapter 28, Vitamin D: production, metabolism, mechanism of action, and clinical requirements. p. 141-9. 4. Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357:266-81. 5. Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, Murad MH, Weaver CM; Endocrine Society. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011 Jul;96(7):1911-30. |