The Histone H4 Colorimetric Cell-Based ELISA Kit provides a lysate-free, convenient, and high-throughput approach for sensitive detection of HistoneH4 protein expression profile in cells. The kit can be used for measuring the relative amounts of HistoneH4 in cultured cells as well as screening for the effects that various treatments, inhibitors (ie siRNA or chemicals), or activators have on HistoneH4.