Vitamin D (25-Hydroxyvitamin D) Test Price in Chandrasekharpur

Test Description

25-Hydroxyvitamin D (25(OH)D), also known as calcidiol, is the major circulating form of vitamin D and the best indicator of vitamin D status. It is formed in the liver by hydroxylation of either vitamin D3 (cholecalciferol, produced in skin on UV-B exposure or from dietary animal sources) or vitamin D2 (ergocalciferol, from plant sources/supplements). The kidney further hydroxylates 25(OH)D to the biologically active 1,25-dihydroxyvitamin D (calcitriol) in a PTH-regulated step. Serum 25(OH)D normal reference: deficiency <20 ng/mL (<50 nmol/L); insufficiency 20–29 ng/mL; sufficiency 30–100 ng/mL; toxicity >100–150 ng/mL. Vitamin D deficiency is extremely prevalent globally (estimated 1 billion people) and is associated with rickets (children), osteomalacia (adults), secondary hyperparathyroidism, and increased risk of osteoporosis fractures. Associations with extra-skeletal effects (immune function, cardiovascular disease, cancer, multiple sclerosis, depression) are intensively studied, though supplementation trials have not consistently shown benefit beyond bone outcomes. High-risk groups: elderly, dark-skinned individuals, obese, institutionalized, malabsorption syndromes.