The Quantikine Human CD31/PECAM-1 Immunoassay is a 4.5 hour solid-phase ELISA designed to measure human CD31 in cell culture supernates, serum, plasma, saliva, and urine. It contains CHO cell-expressed recombinant human CD31 and has been shown to accurately quantitate the recombinant factor. Results obtained using natural human CD31 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 CD31. Range: 0.31 - 20 ng/mL. Sensitivity: 0.078 ng/mL. Time: 4.5 hours