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Calcitriol 1,25-Dihydroxyvitamin D
Test Code16558
CPT Codes
82652
Includes
Vitamin D,1,25 (OH)2,Total
Vitamin D3, 1,25 (OH)2
Vitamin D2, 1,25 (OH)2
Vitamin D3, 1,25 (OH)2
Vitamin D2, 1,25 (OH)2
Preferred Specimen
0.6 mL serum
Minimum Volume
0.25 mL
Instructions
Collect blood in a red-top (no gel) (preferred) or SST (red-top). Allow blood to clot (30 minutes) at room temperature. Centrifuge and separate the serum from the cells and transfer serum to a clean transport tube.
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 28 days
Refrigerated: 28 days
Frozen: 28 days
Refrigerated: 28 days
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Lipemia • Icteric specimens • Plasma
Methodology
Chromatography/Mass Spectrometry
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Set up: Daily; Report Available: 2-3 days
Clinical Significance
This test measures the bioactive form of vitamin D. It is used in the differential diagnosis of hypocalcemia and to monitor patients with renal osteodystrophy or chronic renal failure. This test is not suitable for diagnosis of vitamin D deficiency and monitoring supplementation in most patients. The 25-hydroxyvitamin D test is the recommended test for those purposes (N Engl J Med. 2007;357:266-281).
