DESCRIPTION: The Vitamin D Direct Enzyme Immunoassay is a diagnostic test designed to measure levels of 25-hydroxyvitamin D (25(OH)D) in serum. This assay provides a direct assessment of vitamin D status, including both vitamin D2 and D3, which is crucial for maintaining bone health, immune function, and overall metabolic processes. Clinicians use this assay to diagnose vitamin D deficiency, monitor supplementation, and evaluate conditions such as osteoporosis, osteomalacia, and other disorders related to calcium metabolism.