25-OH-VD Test Kit

Vitamin D is a kind of fat-soluble sterol derivatives, and its main components are vitamin D2 and vitamin D3, which are essential substances for human health, growth and development. Its deficiency or excess is closely related to many diseases, such as musculoskeletal diseases, respiratory diseases, cardiovascular diseases, immune diseases, kidney diseases, neuropsychiatric diseases and so on. In most people, vitamin D3 mainly comes from photochemical synthesis in the skin under sunlight, while vitamin D2 mainly comes from various foods. Both of them are metabolized in the liver to form 25-OH-VD and further metabolized in the kidney to form 1,25-OH-2D. 25-OH-VD is the main storage form of vitamin D, accounting for more than 95% of the total VD. Because it has a half-life (2~3 weeks) and is not affected by blood calcium and thyroid hormone levels, it is recognized as a marker of vitamin D nutritional level.