25-OH Vitamin D

Test Code
VITD

CPT Codes
82306

Preferred Specimen

SST




Minimum Volume
0.5 mL

Transport Container

Serum (gold or red top) Tube



Transport Temperature
Room Temperature or Refrigeration

Specimen Stability
Room Temperature - 1 day; Refrigeration - 7 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross Hemolysis, Turbidity, Quantity Not Sufficient, IV Contamination

Methodology
Chemiluminescence

Setup Schedule

Daily upon receipt



Report Available
Upon completion of analysis

Limitations
Paricalcitol (Zemplar) may interfere with this test.

Reference Range
Vitamin D Status:  Range:
Deficiency < 20 ng/mL
Insufficiency 20 - 30 ng/mL
Sufficiency 30 - 100 ng/mL
Toxicity > 100 ng/mL


Clinical Significance

Vitamin D is a fat soluble steroid hormone that comes in two forms, vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol).  Vitamin D is synthesized from cholesterol upon skin exposure to UVB sunlight or through dietary intake.  Vitamin D is hydroxylated in the liver to form 25-OH Vitamin D which is further hydroxylated in the kidney to form the biologically active form, 1,25-(OH)2 Vitamin D.  The active hormone is tightly regulated by plasma parathyroid hormone levels and serum calcium and phosphorous levels.  The active form, 1,25-(OH)2 Vitamin D, increases the intestinal absorption of calcium and phosphorous, both are required for regulating bone metabolism.  Vitamin D metabolites are bound to a vitamin D binding protein and are circulated throughout the body.  The concentration of 1,25-(OH)2 Vitamin D is 1000 times lower than 25-OH Vitamin D and has a half life of 4 hours.  Due to its half life of 2–3 weeks, 25-OH Vitamin D is the metabolite that is the most reliable clinical indicator of vitamin D status.  Also, 25-OH Vitamin D levels are indicative of the body’s storage levels of vitamin D and correlate with the clinical symptoms of vitamin D deficiency. In the late 18th century, vitamin D was first recognized as an essential dietary component in the prevention of rickets.  Recently, research has indicated that vitamin D deficiency may be linked to chronic diseases such as cancer (breast, colon and prostate), cardiovascular disease, osteoporosis, osteomalacia and several autoimmune diseases among others.





The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.