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Test Name:
Vitamin D2 and D3, 25-Hydroxy (includes Total), by LC-MS/MS
- SBMF No:
31404 - Performance Lab Name:
Toxicology - Test Mnemonic:
VIT D2/D3 - ABN:
May be required – Medical Necessity - CPT Code:
82306 - LOINC Code:
2236-8; 1989-3; 49543-2 - Test Includes:
25-Hydroxyvitamin D2
25-Hydroxyvitamin D3
25-Hydroxyvitamin D, Total - Also Known As:
25-Hydroxyvitamin D2 and D3 - Also See:
30054 Vitamin D, 25-Hydroxy - Spec Type:
Serum - Spec Container:
Gold top (SST) or red top (serum) tube - Pref Vol:
1.0 mL - Min Vol:
0.5 mL - Fasting:
Recommended, but not required - Spec Collect:
Routine venipuncture - Spec Process:
Clot 30 minutes
Promptly centrifuge 15 minutes
Immediately transfer serum to light-protected (amber) plastic tube and freeze - Spec Store Transport:
Frozen
Protected from light - Spec Stability:
3 days (72 hours) refrigerated (2-8°C)
6 months frozen (-20°C) – Do not use frost-free units that undergo repeated freeze/thaw cycles - Methodology:
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) - Use:
Measurement of vitamin D metabolites (25-hydroxyvitamin D2 and 25-hydroxyvitamin D3)
Monitoring vitamin D status - Clinical Significance:
Vitamin D is a fat-soluble vitamin known for its role in preventing bone deformities in children and in optimizing the function of organs (e.g., bone, intestine, and kidney). Recent studies have shown that vitamin D is also linked to protecting the body from a wide range of diseases. Diseases linked to vitamin D deficiency include stroke, cardiovascular disease, osteoporosis, and several forms of cancer, multiple sclerosis, rheumatoid arthritis, type 1 and type 2 diabetes.
Vitamin D exists in two forms, ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D2 does not occur naturally but is manufactured commercially by irradiating the fungal derived component, ergosterol. Vitamin D2 is the predominant form obtained by prescription in the U.S. Vitamin D3 is produced endogenously from the action of ultraviolet light on the vitamin D precursor, 7-dehydrocholesterol, found in the skin. Vitamin D3 is also found in some foods, over-the-counter vitamin D supplements, and products that contain cholecalciferol. Vitamin D2 and D3 are hydroxylated in the liver to form their 25-hydroxy metabolites (25-hydroxyvitamin D2 and 25-hydroxyvitamin D3). These metabolites are further hydroxylated, primarily in the kidneys, to form 1,25-dihydroxyvitamin D2 and 1,25-dihydroxyvitamin D3, which are the highly active and bind to specific vitamin D receptors in target tissues.
Many consider the measurement of 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 by LC-MS/MS to be the “method of choice” because this method is able to differentiate D2 from D3. This differentiation is important when assessing vitamin D status in patients supplementing with D2, which has a greater potential for toxicity than D3 supplementation.
- Reference Range:
25-OH vitamin D levels for bone and overall health in healthy individuals: Severe deficiency <10.0 ng/mL Inadequate 10.0-29.9 ng/mL Sufficient levels 30.0-80.0 ng/mL Excess >80.0 ng/mL Toxic Consistently >150.0 ng/mL - Day Run:
Mon, Thu - Time Reported:
5:00 pm, next day - Test Type:
CHEMISTRY
