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Lab Dep:
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Chemistry
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Test Name:
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VITAMIN D, 25-HYDROXY
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General Information
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Lab Order Codes:
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VDT
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Synonyms:
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Vitamin D Assay; 25-Hydroxycholecalciferol; 25-OH-Vitamin D; 25-Hydroxy D2, 25-Hydroxy D3; Calcidiol
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CPT Codes:
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82306 – Calcifediol (25-OH Vitamin D-3)
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Test Includes:
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Total 25-hydroxyvitamin measured in ng/mL.
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Logistics
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Test Indications:
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The test is used to assess patient’s vitamin D status, evaluate hypo and hypercalcemia and to investigate the causes of osteomalacia and rickets. Also useful in monitoring vitamin D replacement therapy.
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Lab Testing Sections:
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Chemistry (Performed on the St. Paul Campus)
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Phone Numbers:
Minneapolis:
Saint Paul:
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612-813-6280
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651-220-6550
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Test Availability:
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Daily, 24 hours
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Turnaround Time:
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1 – 3 days, performed Monday - Friday
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Special Instructions:
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N/A
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Specimen
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Specimen Type:
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Blood
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Container:
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Red top tube
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Draw Volume:
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1.5 mL blood
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Processed Volume:
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0.5 mL (Minimum: 0.25 mL) serum
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Collection:
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Routine venipuncture, capillary specimens are not recommended
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Special Processing:
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Lab Staff: Centrifuge specimen when clotted, remove serum aliquot into a screw-capped plastic vial. Store at refrigerated temperatures for up to 5 days.
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Patient Preparation:
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None
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Sample Rejection:
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Specimens other than serum, unlabeled or mislabeled specimens
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Interpretive
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Reference Range:
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All ages: 30 – 100 ng/mL
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Critical Values:
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N/A
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Limitations:
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● Gross hemolysis falsely elevates Vitamin D.
● The test cross-reacts with dihydroxylated metabolites of Vitamin D.
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Methodology:
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Direct competitive chemiluminescent immunoassay
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References:
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Liason 25 OH Vitamin D, Product Insert 1/2009, DiaSorin, Inc.
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