Fengqiang Wang, PhD, is associate principal scientist,Sterile Product and Analytical Development, Merck Research Laboratories, 2000 Galloping Hill Road, K15-4-E214Kenilworth, NJ 07033; fengqiang.wang@merck.com
This article reviews the definition of HCPs, risks posed by HCPs, regulatory concerns, commonly accepted ELISA methods for HCP measurement and their limitations, and orthogonal methods available for HCP characterization.