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QuestAssureD™ 25-Hydroxy and Calcitriol 1,25-Dihydroxyvitamin D
Test Code16761
CPT Codes
82306, 82652
Includes
QuestAssureD™ 25-Hydroxyvitamin D (D2, D3) and Calcitriol 1,25-Dihydroxyvitamin D
Preferred Specimen
2 mL serum
Patient Preparation
Fasting preferred, but not required
Minimum Volume
1.2 mL
Instructions
Collect blood in a red-top tube (no gel). Allow blood to clot (30 minutes) at room temperature. Centrifuge and separate the serum from the cells.
Transport Container
Transport tube
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 21 days
Refrigerated: 21 days
Frozen: 21 days
Refrigerated: 21 days
Frozen: 21 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Lipemia • Heparinized or EDTA plasma • Icteric • Serum not separated from serum separator tube (SST) gel or clot within 48 hours
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
Vitamin D originating from dietary and endogenous sources is converted to 25-hydroxyvitamin D in the liver, and subsequently to 1, 25-dihydroxyvitamin D in the kidney. Measurement of both the 1, 25-Dihydroxy and 25-Hydroxy forms provide insights into a variety of medical conditions such Vitamin D status in renal failure, differential diagnosis of primary, secondary and tertiary hyperparathyroidism. Differential diagnosis of hypercalcemia and type I and II inherited rickets.