This protocol is intended to illustrate the process for testing a particular cell type with the IRDye 800CW EGF for eventual use in vivo. A431 (epithelial carcinoma) cells are used in this example because of their over-expression of EGFR. Media considerations and certain cell characteristics will naturally alter this protocol if a different cell line is used. Developed for: Aerius, Odyssey® Classic, Odyssey CLx, and Odyssey Sa Infrared Imaging Systems