Check Your Bone and Immune Health - Vitamin D (25-Hydroxy) Test

The 25-hydroxyvitamin D (25-OH-D) test measures the concentration of the main stored and circulating form of vitamin D in the blood. It is the most accurate and reliable indicator for assessing the body's overall vitamin D status, reflecting both endogenous production in the skin (under the influence of UVB sunlight) and dietary intake. This form is converted in the kidneys to the active form (1,25-dihydroxyvitamin D), which regulates calcium and phosphate absorption and affects numerous vital functions.