The Click-iT® EdU Alexa Fluor® 488 Imaging Kit (Replaces EdU Assay C10083) provides a superior alternative to BrdU assays for measuring cell proliferation. EdU (5-ethynyl-2’-deoxyuridine) is a nucleoside analog to thymidine and is incorporated into DNA during active DNA synthesis. Unlike BrdU assays, which require harsh treatments to permeabilize the cells and denature the DNA for antibody-based detection, with Click-iT® EdU, mild fixation and detergent permeabilization is sufficient for the small molecule-based Click-iT® EdU detection reagent to gain access to the DNA. As a consequence, the Click-iT® EdU cell proliferation kit is not only easy to use, but more accurate and compatible with cell cycle analysis and other intracellular or extracellular targets for truly content rich results.