This assay has high sensitivity and excellent specificity for detection of 1, 25-Dihydroxyvitamin D3. No significant cross-reactivity or interference between 1, 25-Dihydroxyvitamin D3 and analogues was observed. Sample types: serum, plasma and other biological fluids. Range: 123.5-10000 pg/mL. Sensitivity: 49.5 pg/mL. Intra-assay Precision (Precision within an assay): 3 samples with low, middle and high level 1, 25-Dihydroxyvitamin D3 were tested 20 times on one plate, respectively. Inter-assay Precision (Precision between assays): 3 samples with low, middle and high level 1, 25-Dihydroxyvitamin D3 were tested on 3 different plates, 8 replicates in each plate.CV (%) = SD/meanX100;Intra-Assay: CV<10%;Inter-Assay: CV<12%. Time: 2 hours