Detection of hepatitis C virus (HCV) core antigen in chronically infected patients with a simple immunoassay: Gaston R Picchio, Scripps Research Institute, La Jolla, CA; Chander Bahl, Patrick Niven, Ortho Clinical Diagnostics, Raritan, NJ; Patricia Bare, Acad Nacional de Medicina, Buenos Aires Argentina; Veronica Bussy, Lab Citometria & Biologia Molecular S A, Buenos Aires Argentina; Steve Alexander, Ortho Clinical Diagnostics, Raritan, NJ; Donald Mosier, Scripps Research Institute, La Jolla, CA; Federico G Villamil, Fundacion Favaloro, Buenos Aires Argentina; Stephen R Lee, Ortho Clinical Diagnostics, Raritan, NJ