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Labcorp Oklahoma, Inc.
Test Directory


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Vitamin D, 1,25-Dihydroxy (Vit D 1-25-DOH)

Order Name VIT D1-25
Test Number: 3603730
Revision Date 10/20/2018
Test Name Methodology LOINC Code
Vitamin D, 1,25-Dihydroxy (Vit D 1-25-DOH)
Quantitative Chemiluminescent Immunoassay 62290-2 
SPECIMEN REQUIREMENTS
Specimen Specimen Volume (min) Specimen Type Specimen Container Transport Environment
Preferred 1mL (0.5) Serum Clot Activator (Red Top, No-Gel) Refrigerated or Frozen
Alternate 1 1mL (0.5) Serum Clot Activator SST Refrigerated or Frozen
Alternate 2 1mL (0.5) Plasma EDTA (Lavender Top) Refrigerated or Frozen
Instructions Allow serum separator or plain red tube to sit for 15-20 minutes at room temperature for proper clot formation.
Centrifuge and separate serum or plasma from cells ASAP or within 2 hours of collection. Transport Refrigerated or Frozen in plastic aliquot tube.
Stability After separation from cells: Ambient: 72 hours; Refrigerated 1 week; Frozen 6 months.
GENERAL INFORMATION
Testing Schedule Mon, Wed, Fri 
Expected TAT 3-5 Days  
Clinical Use Vitamin D originating from dietary and endogenous sources is converted to 25-hydroxyvitamin D in the liver, and subsequently to 1-25 Dihydroxy vitamin D in the kidney. Deficiencies of 1-25 Dihydroxy vitamin D, the most active form, cause hypocalcemia, osteomalacia, and related disorders. Measurement is useful in: differentiating primary hyperparathyroidism from hypercalcemia of cancer; distinguishing between vitamin D dependent and vitamin D resistant rickets; monitoring vitamin D status of patients with chronic renal disease; and, assessing compliance to therapy. 
Notes This test is used to measure the bio-active form of Vitamin D. This test is also used in the differential diagnosis of hypocalcemia and to monitor patients with renal osteodystrophy or chronic renal failure.
CPT Code(s) 82652
Lab Section Immunology - Serology