This Eagle Biosciences ELISA is based on a Vedolizumab-specific monoclonal antibody (catcher Ab, ImmunoGuide clone19F3). Diluted standards and samples are incubated in the microtiter plate coated with IG-19F3 mAb. After incubation, the wells are washed. A horseradish peroxidase (HRP)-conjugated anti-human IgG antibody is added and binds to the Fc part of Vedolizumab. Following incubation, wells are washed and the bound enzymatic activity is detected by addition of chromogen-substrate. The color developed is proportional to the amount of Vedolizumab in the sample or standard. Results of samples can be determined by using the standard curve. Sample Types: serum, plasma. Range: 6 - 200 ng/mL. Sensitivity: 5 ng/mL. Time: 2 hours ? The drug Vedolizumab (trade name Entyvio?) is a humanized immunoglobulin G1 monoclonal antibody that binds exclusively to the lymphocyte integrin α4β7. Identification of biomarkers might be beneficial for (non-) response and risk factors for adverse drug reactions that might be related to serum drug levels and maintaining the effective concentration in order to potentially avoid some side effects with a reliable method. The specificity of this testsystem is achieved by using a monoclonal antibody named IG-19F3 for the coating of the microtiter plate. This antibody is specific for Vedolizumab only and does not cross react with other lymphocyte integrin α4β7 catchers.