PathHunter® eXpress Cytosolic Tyrosine Kinase (CTK) Activity Assay Kits are cell-based assays used for the identification, screening or profiling of small molecule inhibitors. This assay format cannot be used for functional testing of biologics. The eXpress kits contain everything needed for a complete CTK experiment including cells, detection reagents, media and plates. The pre-validated, frozen eXpress cells have been manufactured for short term use and are provided in a ready-to-assay format that saves time and adds convenience. Assays have been designed for 96-well and 384-well plate analyses.