The BHK (Baby Hamster Kidney Fibroblast) cell line is used as an expression system for viral vaccines and other therapeutic proteins. Our HCP kit is generic in the sense that it is intended to react with essentially all of the HCPs that could contaminate the product independent of the purification process. The antibodies have been generated against and affinity purified using a mild lysate of BHK cells. The resulting antibodies have then been characterized against 3 commercial cell lines used to produce various viral and protein products. This analysis indicated the vast majority of HCPs were conserved among multiple BHK cell lines and product purification processes. Our assay validation has determined that the LOD for this kit is ~0.4ng/mL.