A Vitamin D Deficiency Test, also known as a 25-OH Cholecalciferol, 25-OH Vitamin D Test, Calcidiol Test, or Vitamin D3 Test, measures your body's Vitamin D levels to assess overall bone health and immune system function.
It measures the concentration of 25-hydroxyvitamin D, the major circulating form of vitamin D in the body, studying which allows valuable insights into vitamin D levels and helps healthcare professionals determine if there is a vitamin D deficiency or not. The two most common forms of vitamin D that are tested are 25-hydroxyvitamin D2 (25(OH)D2) and 25-hydroxyvitamin D3 (25(OH)D3). These are the major circulating forms of vitamin D in the body and serve as indicators of an individual's vitamin D status.
Types of Vitamin D Test
- 25-Hydroxy Vitamin D Test (25-OH Vitamin D Test): This is the most common and comprehensive test, measuring both Vitamin D2 and D3 levels.
- Vitamin D2 Test: Specifically measures Vitamin D2 levels, which come from plant-based sources and supplements.
- Vitamin D3 Test: Specifically measures Vitamin D3 levels, the more biologically active form synthesized by the skin and found in some animal-based foods.
- 1,25-Dihydroxy Vitamin D Test (1,25-OH Vitamin D Test): Measures the active form of Vitamin D, typically used for specific medical conditions.
These tests help assess Vitamin D status and guide appropriate interventions to maintain health. In practice, when you request a "Vitamin D Deficiency Test" from your healthcare provider, they will usually measure both Vitamin D2 and Vitamin D3, giving you a total Vitamin D level. This is because both forms are important for assessing your overall Vitamin D status. However, if you have a specific need to measure just one form, you can request to focus on that particular form.