Cayman's DYKDDDDK-Tag Detection ELISA Kit provides the ability to rapidly assess the levels of DYKDDDDK-tagged proteins at each stage of the expression and purification process. This permits the user to quickly monitor expression efforts and follow protein loss or enrichment at each purification step. This assay is designed for the rapid, semi-quantitative screening of cell lysates and affinity column fractions for DYKDDDDK-tagged proteins. It is intended to serve as a substitute for SDS-PAGE, thereby expediting the screening of affinity column fractions.