The Quantikine Human B7-H3 Immunoassay is a 4.5 hour solid-phase ELISA designed to measure human B7-H3 in cell culture supernates, serum, plasma, and urine. It contains NS0-expressed recombinant human B7-H3 and has been shown to accurately quantitate the recombinant factor. Results obtained using natural human B7-H3 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 naturally occurring human B7-H3. Range: 0.78 - 50 ng/mL. Sensitivity: 0.274 ng/mL. Time: 4.5 hours