Used in research settings to measure levels of 1,25-dihydroxyvitamin D in human serum or plasma samples. This assay helps assess vitamin D metabolism and activity, which is critical in studying bone health, calcium regulation, and immune function. Commonly applied in clinical research on diseases such as osteoporosis, chronic kidney disease, and autoimmune disorders where vitamin D signaling plays a regulatory role. The kit enables high-throughput, accurate quantification, supporting studies on hormonal pathways and therapeutic interventions targeting vitamin D receptors.