1,25-Dihydroxyvitamin D

1,25-dihydroxyvitamin D is the most biologically active form of vitamin D, produced primarily by the kidneys. This test measures circulating levels of active vitamin D in your blood. Vitamin D is essential for calcium absorption, bone health, immune function, and mood regulation. Low levels may indicate kidney disease, vitamin D deficiency, or calcium disorders, while abnormally high levels can occur with excessive supplementation or certain granulomatous diseases. This test is particularly useful for evaluating bone health and metabolic disorders.