Vitamin D Test, Detects deficiencies in Vitamin D (independently monitoring both Vitamin D2 and D3 status by LC-MS/MS) as a potential cause of health problems ranging from osteoporosis to cardiovascular disease.Why test Vitamin D? Vitamin D deficiency is very common, particularly in northern climates with little sunshine. Vitamin D has been found to be important in protecting the body from a wide range of diseases, including cardiovascular disease, stroke, osteoporosis, osteomalacia, cancer, autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, diabetes (types 1 and 2), and schizophrenia. California State residents: California State health law does not allow the testing of specimens collected or mailed to California without a written order from a health care professional licensed to prescribe in California (MD, ND, DC, DO, NP, and LAc).