Vitamin D

It is vital for strong bones. It also has important, emerging roles in immune function and cancer prevention. Deficiencies at any stage of life can have devastating consequences. Similarly, vitamin D toxicity resulting from overmedication can cause serious hypercalcemia. Vitamin D consists of two bioequivalent forms: 

  • Vitamin D2, which is obtained from vegetable sources (dietary sources, supplements)
  • Vitamin D3, which is derived from both endogenous (synthesized from cholesterol through sun exposure) and exogenous (animal diet) sources.

Vitamin D deficiency is more common than previously believed, especially among adolescents, women, and the elderly. For example, studies have shown that more than 50% of the elderly and an equal proportion of women of any age undergoing treatment for osteoporosis have inadequate levels of vitamin D. While treatment with vitamin supplementation is easy and inexpensive, many affected individuals go undiagnosed and untreated.

Patient Care

Who Should Be Tested?

 

The following should be tested for Vitamin D deficiency:

  • Individuals receiving therapy to prevent or treat osteoporosis.
  • Elderly people, especially those with minimal exposure to sunlight.
  • Patients with signs and symptoms of hypocalcemia or hypercalcemia.
  • Children and adults with suspected rickets and osteomalacia, respectively.
  • Patients receiving vitamin D therapy who do not demonstrate clinical improvement.

Vitamin D deficiency is more common than previously believed, especially among adolescents, women, and the elderly. For example, studies have shown that more than 50% of the elderly and an equal proportion of women of any age undergoing treatment for osteoporosis have inadequate levels of vitamin D. While treatment with vitamin supplementation is easy and inexpensive, many affected individuals go undiagnosed and untreated.

Patient Impact

The potential impacts of Vitamin D deficiency testing are:

 

  • Establishing the need for replacement therapy and guides appropriate treatment, avoiding under-medicating the patient.
  • Detecting the rare occurence of Overtreatment, occurring only with long-term replacement at doses of almost 10,000 U/day or more.

 

Benefits of Testing

  • Reliable assessment of vitamin D stores.
  • Diagnosis of vitamin D deficiency.
  • Differential diagnosis of causes of rickets and osteomalacia.
  • Monitoring vitamin D replacement therapy.
  • Diagnosis of hypervitaminosis.

 

How Does the Acquity Labs Test for Vitamin D analysis differ?

  • Acquity Labs Vitamin D deficiency test offers key differentiators
  • Acquity Labs uses validated LC-MS/MS assay.

 

Technical aspects of LC-MS/MS include:

 

  • Accurate and precise, due to internal standard and physico-chemical methodology.“
    • Gold standard” method.
    • Uses standards of defined concentrations.
    • Facilitates lab-to-lab and assay-to-assay comparisons with other MS/MS and HPLC assays.
    • Results may be used to determine if target therapeutic levels (25-80 ng/mL) have been obtained.
  • Not subject to lot-to-lot variation, reagent availability issues, or licensing fees associated with proprietary kits.
  • Faster than HPLC.
  • Separates 25OH VitD2 and 25OH VitD3. In patients who show no improvement on replacement therapy (VitD2), absence of rise in 25OH VitD2 may indicate noncompliance or malabsorption, whereas rise in 25OH VitD2 and total vitamin D levels may indicate vitamin D resistance.
  • Uses a smaller specimen volume than HPLC (0.25 mL).
  • Requires fewer repeat analyses as a result of a wider reportable range.
  • Provides 25OH VitD2 and 25 Vit D3 levels in addition to the total vitamin D level. This allows assessment of the source of the deficiency and also facilitates treatment monitoring.
  • The total 25OH Vit D measured with the new assay correlates well with our previous methodology, which in itself has been shown to outperform other laboratories and tests.
  • Improves on accuracy and precision of ligand assays, including our previous assay: ~10% CV at low 25OH Vit D levels (10 ng/mL).