Calcidiol is a form of vitamin D that is produced in the liver from cholecalciferol, which is obtained from sunlight exposure or dietary sources. It plays a crucial role in maintaining healthy levels of calcium and phosphate in the body, which are essential for bone health and overall metabolic functions. Once formed, calcidiol is converted into its active form, calcitriol, in the kidneys. This active form helps regulate calcium absorption in the intestines and supports various bodily functions, including immune response and cell growth. Monitoring calcidiol levels can be important for assessing vitamin D status in individuals.