The Quantikine? Human Vitamin D BP immunoassay is a 3.5 hour sandwich-type solid phase ELISA designed to measure human Vitamin D BP in cell culture supernates, serum, plasma, and urine. It contains HEK293-expressed recombinant human Vitamin D BP and has been shown to accurately quantitate the recombinant factor. Results obtained using natural human Vitamin D BP showed linear curves that were parallel to the standard curves obtained using the Quantikine? kit standards. These results indicate that this kit can be used to determine relative mass values for natural human Vitamin D BP. Read more about the Vitamin D BP specificity in this White Paper. Range: 6.25 - 100 ng/mL. Sensitivity: 0.338 ng/mL.