Test Code: 3005CPT: 82306
|Tests Included||25-OH Vitamin D, Total; Vitamin D, 25-OH, D3; Vitamin D, 25-OH, D2|
|Use||Vitamin D levels are monitored for a number of uses ranging from dietary absorption, parathyroid function, bone weakness/malformation, metabolism of calcium, and to help with measuring Vitamin D treatment effectiveness.|
|Clinical Utility||Vitamin D is a fat soluble vitamin that is important in the regulation of calcium and phosphorous in the body. Vitamin D deﬁciency has been linked to rickets, osteoporosis and osteomalacia. It has also been associated with many other diseases such as cancer, cardiovascular disease, diabetes, and autoimmune disorders.
There are two biologically active forms of Vitamin D, the D2 (ergocalciferol) and D3 cholecalciferol). Both forms are commonly found in fortiﬁed foods and commercially available supplement products. The D2 and D3 products have been used in high potency pharmaceutical grade formulations used to treat speciﬁc conditions. Vitamin D2 is derived from plant or fungal sources, while Vitamin D3 is derived from animal sources and is the form synthesized in the skin following exposure to sunlight.
Vitamin D is converted into the 25-hydroxy Vitamin D (25-OHD) metabolite in the liver, which is the major circulating form of Vitamin D used for assessing Vitamin D status. Liquid chromatography coupled with mass spectrometry (LC/MS/MS) is the gold standard technique for measuring D2 and D3. It is the only technique that is able to measure both D2 and D3 concentrations individually.
By comparison, immunoassay-based Vitamin D tests can only provide indirect measurements and produce inaccurate results for patients taking supplements containing D2.
|Intended Patient Population||18+ and Older Adult Males & Females|
|Patient Preparation||None Specified|
|Tube||Red, Green, Tiger|
|Volume||4mL Whole Blood (100 µL Serum/Plasma)|
|Min Sample Volume||0.05 mLs|
|Reference Ranges||Total Vit D - M & F ≥ 18 yrs old; 30-50 ng/mL|
|Analytical Measurement Range||1.5-100.00 ng/mL|
|Critical Values||> 80 ng/mL|
|Test Turnaround Time||5 Days|
|Limitations||Values of vitamin D vary with exposure to sunlight and dietary supplementation.|
|Specimen Stability||8 Days RT
|Reject Criteria||Gross Hemolysis, Expired Sample, Insufficient Quantity|
|Laboratory Developed Test (LDT)||Yes|
|CMS Guidance||LCD L36692|